SCIENTIFIC ABSTRACT BELOV, K. P. - BELOV, K. P.

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69703 S/126/60/009/03/029/033 E032/E414 Temperature Dependence of Spontaneous Magnetization in a Monocrystal of a Manganese Ferrite in the Low Temperature Region magnetization direction [1113 was parallel to the ,a of the cylinder. The mea~surements of the magnetization were carried out in a solenoid by a ballistic method. A cryostat (Ref 8) was introduced into the solenoid., The magnetization was measured to + 1% and the temperature to + 0.5 Fig 1 shows a plot of the magnetization (at c-onstant temperature) as a function of the applied field. As can.be seen from this figure, the saturation magnetization is reduced by 1/3 ongoing from 4.2 to 319*X. Fig 2 shows a plot of the spontaneous magnetization as a function of T3/2. The dotted curve represents a plot of the spontaneous magnetization as a function of T2. It is found that the former relationship is in better agrcement with experiment. The slope of the straight line in the case of the T3/2 plot Is in good agreemeni with theoretical calculations (Ref 3 and 4). It is found that the T3/2 law holds right up to temperatures above room temperature, Card 2/3 which is in accordance with the results of Dyson (Ref 9), 697(9 s/126/60/009/03/029/033 E032/E414 Temperature Dependence of Spontaneous Magnetization in a Monocrystal of a Manganese Ferrite in the Low Temperature Region who showed that the spin wave theory leading to the T3/2 law can be extended to temperatures in the range between absolute zero and one half of the Curie temperature* The Curie temperature for the sample used in the present work was 563 K. There are 2 figures and 9 references, 6 of which are Soviet, 2 English and I French. ASSOCIATIONtMoskovskiy gosudarstvennyy universitet im M.V.Lomonosova (Moscow State University imeni M.V.Lolpanosov) SUBMITTEW July 139 1959 Card 3/3 85700 S105616010381006104310491XX Boo6/bo7o A UT720; 11-111/e,111olv', //K'11.111. , Belo v , V. F. , Pop ova, A. A. TITLE: Single Crystals of Magnesium Manganese Ferrite4ith a Narrow Ferromagnetic Resonance Absorption Curve PERIODICAL:, Zhurnal eksperimentalinoy i teoreticheskoy fiziki, 1960, Vol. 38, No. 6, pp. 1908 - 1910 TEXT: The present "Letter to the Editor" gives some experimental results obtained from some apinel-type ferrites with a narrow vesonance absorp- tion line. The line width AH was measured fjr different magnesium manganese ferrites with different oxide ratios of Mn and Mg. The single crystals studied were bred by the method of Verneuille. The specimens were spherical in shape with a diameter of 0.8-1 mm; their su-rfaces were polished. The measurements were made at a frequency of 9470 Me/see. The results of measurement, namelyg the values of AH, of the saturation magne- tization 4nIs, and of resistivity Q are shown in Table 1. Fig.1 shows the anisotropy of the line width in the (110) plane of a specimen having the -composition last mentioned in the Table at room temperature (continuous Card 1/* 85700 Bi ngle Crystals of Magnesium Manganese 8/056/60/038/006/043/049/XX Ferrites With a Narrow Ferromagnetic Boo6[BO70 Resonance Absorption Curve curve) * The anisotropy of AH at room temperature had an amplitude of (3-5 � 0-5)oe.' The broken line shows the anisotropy of the resonance field H . The anisotropy character of AR is in agrooment with the p phenomenological calculations of.f takiy and L. V. Kurbatov Skro (Ref-5). Fig.2 shows AH, 47cis, an(I the constant of magnetio anisotropy X as functions of T (in the temperature range 0 - 3000C) for a specimen blying the composition last mentioned in the Table. There are 2 fig- ures, I table, and 5 references: 3 Soviet and 2 US. ASSOCIATION: Institut kristallografii Akademii nauk SSSR (Institute of Crystallography of the Academy of Sciences UaSRJ SUMITTED: March 18, 1960 C ard 2/A_Z_1 85703 B/056/60/038/006/046/049X Boo6/B07O AUTHORS: Belov, K. P., Goryaga, A. H., Lin.) Chzhan-da EleTtrical and Galvanomagnetic PropertiJof Lithium TITLE: Ferrite Chromite in the Vicinity-o -the Compensation Point A PERIODICAL: Zhurnal eksperimentallnoy i teoreticheskoy fimiki, 1960~ Vol. 38, No. 6, pp. 1914 - 1915 TEXT: Some ferrites. showing a compensation point (0k) (in which the mag- netic moments of the..sub-lattices are in equilibrium) exhibit strongly anomaloue'temperature dependence of the spontaneous magnetizationg'and the magnetostrictive properties above and below "k are largely different. In gadolynium ferrite garnetv for example? they are determined below Ok essentially by the gadolynium oub-latticav and above Ok by the iron sub- lattice. Further studies of the role of aub-lattices in ferrimagnetism are communicated in this "Letter to the Editor". Electrical and galvano- magnetic effects in lithium ferrite chromite with a compensation point Card 1 N, 85703 Electrical and Galvanomagnetic Properties 3/056/60/036/006/046/049/XX of Lithium Ferrite Chromite in the BO06/BO7O Vicinity of the Compensation Point were measured. Fig.1 shows the temperature dependence of the longitudinal galvanomagnetic effect for different magnetise field strengths for L12O*2-5Fe 203.2-5Cr2O 30 The temperature dependence of the electrical re- sistance was measured for the same ferrite. Fig.2 shews logR.f(I/T) for d.c. (curve 1) and a.e. (200 ke/sec, Curve 2). The temperature dependence of magnetization at H-250oe is also plotted. The behavior cf the indivi-- dual curves is discussed. The bend of the curves at 0 k is to be attiibut- ed, according to Ye. A. Turov and Yu, F. Irkkin, to the compensation of thevolume fields of the magnetic sub-lattices at 0 k' There are 2 fig-- ures and 5 references: 2 Soviet, 2-French~ and I Belgian. ASSOCIATION: Moskovskiy gosudarstv-ennyy universitet (Mos,30W state University) SV13MITTED: March 29, 1960 0 ard 2/0,, 8L-392 S/056/60/039/004/010/048 B004/B07O 'Ito0 AUTAORS.- Belov, K. P., Pediko, A. V. TITLE; Anomalies in the Temperature Dependence of Coercive Force in PerriteVGarnets of Rare Earth Elements in the Region of the Compensation Point PERIODICAL: Zhurnal eksperimentallnoy i teoreticheskoy fiziki, 1960, Vol. 39, No. 400), pp. 961-964 TEXT: In an earlier'work (Ref. 2), the authors found anomalies in the temperature dependence of the coercive force H. of ferrite garnets of rare earths (3M20Y5Fe 0 ; M - 2d, Dyq Hot ate.) in the neighborhood of WT- A- the compensation po'int Ok (Ref. 1). ?n the present paper they give a detailed report of their investigations. As is shown in Fig. 1, for polycrystalline 3Gd203' 5Fe203 1 Hc increases in the neighborhood of e k (9 k = 120C) to 100 oersteds, decreases strongly and again increases to the same value so that the curve H. = f(T) shows a "splitting" of the Card 1/3 8092 Anomalies in the Temperature Dependence of S/05 60/039/'004/010/048 Coercive Force in Ferrite Garnets of Rare B004YI3070 Earth Elements in the Region of the Compensation Point maximum. The resultant IS of spontaneous magnetization tends to zero at Ok, yet R. is not vanishing on account of the struotural defects of the ferrite crystal. 2i-g. 2 shows that the anomalies continue to exist for different densities of gadolinium. ferrites (3-15 9/CM3, 5.9 g/cm3), but become smaller as the density increases. The anomaly is less affected by thermal treatment (quenching, 4 hour heating, Fig. 3) than by the change in density. Fig. 4 shows the curves H. . f(T) for monocrystalline .3Gd203*5Fe203; 3HO203.5Fe 203 , and 3Er 203-5Pe 203 (compensation temperature +16, -136, and P-19500- Here, the region of anomaly is so small that it is hard to observe experimentally tho splitting of the maximum. The authors assume a single domain structure for which Hc,~..oKlr-a holds (K = constant of magnetic anisotropy, IS - resultant spontaneous- magnetization). since K changes little and IS decreases rapidly, there occurs a strong increase of H.. The authors think that the observed broadening of the absorption line of ferromagnetic resonance (Ref. 4) Card 2/3 8092 Anomalies in the Temperature Dependence of S/05 60/039/004/010/048 Coercive Force in Ferrite Garnets of Rare B004Y~070 Earth Elements in the Region of the Compensation Point is related to the anomalous increase. of Ho. They mention a paper of K. M. ,Bol I shova and 11.1. A. Yelkina (Ref - 3) and thank V. A. Timof eyeva f r bingle crystal.s supplied.,.There are 4 figures and 4 :.,eferences: 2 Soviet, 1 French, and 1 British* ASSOCIATIOk: Moskovskiy gosudarstvennyy universitet (Moscow State University) SUBMITTED: May 16, 1960 Card 3/3 NNOM I IN B3WV.,K.P. YTSWA, M.A.; I&MUSNA, A.M. Magnetic properties of the lanthanum qjd praseodymium orthoforriten in the partial substitution of the Ys-"' ions for AD+ ions. -zhur. eksp. i teor. fix. *39 no-4: 1148-U~O 0 160. .(MIRA 3.3411) 1. Moskovskiy goeudaretvenny7 universitst. (Rare earth farratea-Magnatic properties) 88426 S/02~~60/039/006/011/063 BOO 056 0 47/ lls-e twee) AUTHORS: Belov, K. P., Malevskaya, L. A., Sokolov, V. 1. TITLE: Resonance and Magnetic Properties of Garnet-type Yttrium Ferrites at Low Temperatures PERIODICAL: Zhurnal eksperimentallnoy i teoreticheskoy fiziki, 1960, Vol- 39, No. 6(12), pp. 1542-1547 TEXT: The authors investigated the temperature dependence of the anisotropy of the resonance field and the resonance line widths of single- and poly- crystalline yttrium ferrite specimens DY2 03,. 5Fe203) with garnet structure in the temperature range 2 - 3000K. At the same time, line widths and magnetization curves in static fields were measured on polycrystalline specimens. The ferromagnetic resonance was investigated at 8500 Mc/sec. For the temperature measurement, a copper constantan thermocouple was used. The crystals were grown by V.A. Timofeyeva at the Institut kristallo- grafii AN SSSR (Institute of Crystallography of the AS USSR). Fig. 3 shows the measured temperature dqrendence of the resonance field for poly- crystalline (1):and monoorystalline specimens (2). The results obtained Card 1/# 88426 Resonance and Magnetic Properties of Garnet- S/056/60/039/006/oli/063 type Yttrium Ferrites at-Low Temperatures Boo6/B056 by measuring the resonance field strength in dependence of the direction relative to the crystallographic axes in the (110)-plane ~in which all main axes were located) are for T - 300, 77, 20, and 2.0 K in the four diagrams shown in Fig. 2. Measurements of the temperature dependence of the ferromagnetie resonance absorption line widths showed that the ferro- magnetic resonance absorption in yttrium ferrite garnets shows practically no anisotropy, not only af~: boom temperature, but aloo at helium temperaturn The line width &H increases with de;reasing tempeiaturs, where single crys- tale between 20 and 400Khave steep maxima. At 40 K the line width is more than 15*times as great as at room temperature. Polycrystalline specimens have a much lower and broader maximum (4 - 60 0K). The results obtained are compared with those obtained by Dillon, Spencer, Kittel et al. As a measurement of the static magnet12ation curvesshowed, magnetic viscosity is large in the temperature range of the line width oaxima. The authors thank Professor A. I. Shaltnikov for his interest and advice and V.-k.. Timofeyeva for placing single crystals at their disposal. There are- 6 figures, 1 table,-and 4 references: 1 Soviet and 3 us- ASSOCIATION: Ifoakovskiy goaudaretvennyy universitet Noecow State Uni- versity) Card 2/,f ZBDANOV,q Germain Stepanovich; BELOT, W.V., akad., retsenzentp APJMMT, V.I., Prof., retaenzent; BELOTp K-P-j prof.p retsenzent; ZAKHAROTA, X.I.9 prof., retaenzent; LwMmq G.Se-9 red.; GEORGIYEVA, G.I., tAbn. red.., [Sdj"i#:--state pbysical Fizika tverdogo tela. Moskva, Ivi-vo Hook. univ., 1961. 500 p. (MIRA 14-t6,) (Soj~ds) 20120 S/181/61/003/002/018/050 4,300~/1~7) 115-9 B102/B204 AUTHORS: Belov, K. P., Pakhomov, A. S., and Talalayeva, Ye. V. TITLE: Measurement of the galvanomagnetic effect in ferrites near Curie point PERIODICAL: Pizika tverdogo tela, v. 3, no. 2, 1961, 436-440 TEXT: When measuring the galvanomagnetic effect, the magnetostriction, and other phenomenap it is,necessary to take the effect produced by magnetocaloric effect occurring in the adiabatic application of the magnetic field in the ferromagnetic specimen into account. Por the purpose of excluding the error arising by this effect (which becomea considerable near Curie point), measurements are not carried out immediate- ly after the application of the field (adiabatic measurement), but only some time later, when the temperature equilibrium between specimen and the surrounding medium has been established (isothermal measurement). Whereas in metallic ferromagneti2s the isothermal conditions are easily realizable, this presents difficulties in the case of ferromagnetic semiconductors because of their low thermal conductivity, and when Card 1/4 20120 S/181/61/003/002/018/050 Measurement of the galvanomagnetic B102/B204 measuring the galvanomagnetic effect, considerable errors may arise. In the present paper, the conditions occurring in the measurement of the galvanomagnetic effect are investigated, above all the effect produced by the adiabatic temperature increase occurring when applying the field. K. Zaveta assumed that the maximum of the galvanomagnetic effect of the paraprocess near Curie point, which the authors discovered in ferrites, is exclusively a consequence of the effect produced by a magnetocaloric effect. It is now shown that the conclusions drawn by Zaveta are incorreot. The paper by Zaveta (FTT, a, w6, 196o) is first discussed in detail. For the change in state due to applying the field, Zaveta gave the following form,ula: d R/R - aH 2/3 + bHi here the first term makes the contribution of the "true" galvanomagnetic effectf and the second makes the contribution of the "wrong" galvanomagnetic effect. This formula is, however, wrong, 2/3 2/3 and it ought to read: 4R/R = aH + WH , because all even effects near the Curie point depend in the same manner on H (Viz. ~ H 2/3). From this wrong formula there result also the wrong conclusions drawn by Zaveta. For the purpose of being able to estimate the effect Card 2/4 203.20 S/181/61/003/002/'013/050 Measurement of the galvanomagnetic B102/B204 produced by the magnetocaloric effect, it is necessary to compare a and b'. The sum of the coefficients (a+bl) may be determined from the measurements of AR/R - f(H213). b' (which Zaveta calls b), is proved to be wrongly determined by Zaveta. The method he used is not at all suited for determining b'. Here, the equations AT T An C 61 dT H and 40 - -E4T/k6~ are used for calculating the "wrong" galvano- magnetic effect. Herefromp 6 (Lq AH is obtained (6 R/R)T --VE) - CHke 6T for the Curie point. (a specific magnetization). For Mn ferrite single crystals thus (AR/R)G -6.9-10-4 results from experimental determinations of the individual quantities (data obtained by other authors) and (,A R/R) - -44.2-10-4 is obtained from the authors' own 11wr data. Thus, the Ang" effect is smaller by a multiple,than the "true" effect. The "magnet ocal oric 11 temperature increase AT at Curie point is found to be 0-0700 and causes a change of 6-3% of the Card 3/4 20120 3/161/61/003/002/018/050 Measurement of the galvanomagnetic B102/B204 maximum resistance change It follows herefrom that the maximum of the true galvanomagne.tio effect of ihe paraprocess at Curie point actually exists and is not only due to an "adiabatic" increase of -resistasice.. The existence of this maximum is proven also by the existence of breaks in the log q(l/fl-curves in the Curie point of these ferrites. It may occur only in such ferrites as have a low activation energy E. M. A. Krivoglaz and S. A. Rybak are mentioned. There are 7 Soviet-bloc referenoeso ASSOCIATION:. Moskovskiy gosudarstvennyy universitet im. M. V. Lomonosova, Fizicheskiy fakulltet (Moscow state University imeni M. V. Lomonosov, Division of Physics) SUBMITTED: May 10, 1960 Card 4/4 S/18ij6l/003/005/014/042 .31OI/B214 W4 AUTHORS i Belov, K, P. and Belov Ve Fe TITLEt The problem of the anomalous increase of the line width -of ferromagnetio absorption in ferrites near the Curie point PERIODICALt Pizika tverdogo tela, ve 3, no# 51 19619 1425 - 1427 TEM Reference is made to the fact that there is not only an anomalous increase AR of the width of the ferromagnetic resonance line near the Curie point, but also an increase of the coercive force H a in poly- crystals as well asin single crystals. It is concluded that both the phenomena are caused by the 'inhomogeneity of the ferrite structure rather than by the heat fluctuations of the simultaneous magnetization. Experi- ments were made on single crystals of Mn and Mg-Mn ferrites 5o - 6o mm long and having diameters of 5 - 7 mm. The temperature dependence of H a near the Curie point and the initial magnetic permeabilityp 0 (in a field of 0-005 oersted) were measured with an astatic magnstometer. The tem- Card 1/ 23109 S/181/61/003/005/014/042 The problem of the anomalous**@ B101/B214 perature dependence of tH was measured in a short eircuited waveguide section at a sphere, 0.8 am in diameter out out of ferrite crystals. The results for ferrite with/aifferent hausmannite content are shown graphi- dally. It is concluaeVthat the.broadening of &H and the increase of R have the same origin#~`On accou~l of the inhomogeneities of the ferrite there occur fluctuations in th4-spontaneous magnetization near theLCurie point, giving rise to a "magn6tically heterogeneous" state. This causes scattering of the resonance frequencies near the Curie point. A.A. Popova is thanked for making available the ferrite single crystal. An analogous study made by A. Clogston (see below) is'mentioned. There are 4 figures and 6 references$ 5 Soviet-bloo and 3 non-Boviet-bloo. The 3 references to English-language publications r.ead as followas 0. Rodrigue, J. Pippin, W. Wolf and C. Hogan, Trans.IRE an Microwave Theory Tech. UTT 1 831 1958; P. -G. de Gennes, C."Kittel aiia A, Portis, Phys. Ref., ;,fj 2, 1959; A. Clogston, R. Suhl, P. Anderson, L. Walker, Phys. Chem. Solids,.!, 159, 1956. ASSOCIATIONt Inatitut kristallografii AN SSSR, Moskva (Institute of Crystallographyp AS USSRf Moscow) Card 2/y 9 73M 70o 8/18 61/003/008/031/034 X B102 2ti B111 s . I AUTHORS: Belov, K. P., and Svirina, Ye. P. TITLEt Hall effect in monocrystalline manganese ferrites PERIODICALs Fizika tverdogo tela, v. 30 no. 8t 1961, 2495 2497 TEXT: The changes of the number of carriers and of their mobility in monocrystalline manganese ferrites are studied as functions of temperature and composition. The crystals were grown by Vernsuill a method and displayed an excess of hausmannite as compared to the stoiohiometric composition. Experiments showed that the Hall constant Ro (for this classical determina- - 38 K. P. Belov, Ye. P. tion of R in ferromagnatic substances see Ref 0 Svirinap ZhETF, 11, 1212, 1959) was negative for the ferrites examined by the authors. The carrier concentration was calculated from R M r/ne, 0 where Y">--l is a oonS'int characteristic of electron scattering in the semi- conductor. Measurements in monocrystalline manganese ferrites revealed that the number of conduction electrons rises with rising temperature. 1n n is a linear function of I/T, and the aotLvation energy of conduction Card .1/2 27301 S/161/61/003/008/031/034 Hall effect in monoorystalline... BII1/B1O2 electrons is determined from its slope. From the 1n n - f(l/T) curves it follows that monoorystalline manganese ferrites with an excess of hausmannite are typical semiconductors. Substitution of Fe ions by Mn ions leads to an increase of aotivation-energy and to a decrease of the number of electrons, which in turn results in a decrease in reeistivity,. The fact that the mobility decreases with increasing temperature indicates that an electron exchange between ions of.variable valencies, as assumed by E. Verwey and J. de Boor (Ref. 61 Rea. Trav. Chim. Pays. Boo., 51, 531, 1952) is not predominant in the conduction mechar4m of the ferrites studied. The decrease of mobility with rising temperature shows that conduction elect are predominantly scattered by lattice vibrations. A. A. Popov is thanked for having supplied the single crystals, and V. L. Boneh-Bruyevioh, Doctor of Physical and Mathematical Sciences, for discussions. There are 2 figures and 6 references, 3 Soviet-bloo and 3 non-Soviet-bloc. ASSOCIATIONt Moskovakiy goeudaretvannyy.universitet im. M. V. Lomonosova (Moscow State University imeni M. V. Lomonosov) SUBMITTEDt April 5, 1961 Card 2/2 32650 S/126/61/012/003/002/028 7100 (1a'5~'11qVj11V7111a,3) EO39/El35 AUTHORSs Belov, K.P,-,-Belov, V.F*j Malevskayal L.A*j -Tvd~o, "A.V., and Sokolov, V.I. TITLEs Concerning the anomalous temperature dependence of the width of the ferromagnetic resonance absorption lines in ferrites PERIODICAL: Fizika metallov i metallovedeniye, v.12, no.5, 1961, 636-643 TEXT; An investigation was made of the temperature dependence of the width of the ferromagnetic resonance absorption lines in ferrites with spinel and garnet structure (mono-,and polycrystalline) in three temperature regionss near the Curie point, in the neighbourhood of the magnetic compensation point, and in the low temperature region. At the same time measurements were made of the temperature dependence of magnetic characteristics in static magnetic fields. It is shown that for monocrystalline magnesium-manganese ferrit.e (6.9% MgO, 37.3% MnO, 55.916' Fe203) the width of the resonance absorption line &H increases rapidly at about 550 OK- For polycrystalline yttrium ferrite LH card 1/ 3 32650 S/126/61/012/005/002/028 Concerning the anomalous .... E039/E135 remains fairly constant up to a temperature of about 560 OK at which a sharp increase again occurs; in the case of lower density ferrites of the same composition &H is much greater at low temperatures but falls to approximately the same value as for the higher density ferrite at 560 OK. In the case of the monocrystallIne ferrite (2.2% M90, 54% MnO, 43.6~i Fe2Oi) there--is a very sudden increase in 1%-H and also the coercive orce Hc at the Curie point -412 OK. For the garnet-gadolinium oxide f err� t eAH and H. show a rapId Increase at -270 OK. At low temperatures the ratio 4H/LHK where tilfK is the line width at room temperature is given for the case of the garnet- yttr1um ferrite; a marked maximum occurs about 40 OK for the monocrystalline form and at about 10 OK for the polycrystalline form. It is demonstrated that the effect of small amounts of terbia produces a very marked effect on the temperature dependenza of LH/ AHK for Y203. The temperature dependence of the magnetisatlon and coercive force in weak fields for garnet- gadolinium ferrite at low temperatures is also investigated. In the garnet-gadolinium ferrite there are the following types of Card 2/ 3 32650 C Ioncerning the anomalous S/126/61/012/005/002/028 E039/EI35 interaction between ionas a) Strong negative interaction between ions Fe Fe 3+_ 3+ b) Weak positive interaction between ions Gd Gd c) Weak negative interactions between ions Fe34,_Gd3+. G.V. Skrotskiy and L.V. Kurbatov are mentioned in the article. There are 10 figures and 15 references: 9 Soviet-bloc and 6 non- Soviet-bloc. The English language references read as followss Ref. 3: R. De Genneta, C. Kittel, A. Portia. Phys. Rev., 1939, v.116, 323. Ref.10: A. Kip. Rev. Mod. Phys., 1953, v.25, 229, 7. Ref. ll~ B. Calhounq J. Overmeyer, W. S 'mith. VY Phys. Rev., 1957, V-107, 993. Ref.13t J. Dillon, Phys. Rev., 1958, v.111, 6. ASSOCIATIONt Institut kristallografil. AN SSSR (Institute of Crystallography, AS USSR) Fizicheskiy fakulltet MGU Card 3/3 (Faculty of Physics, MGU) SUBMITTED: January 2, 1961 30058 1141 3/048/61/025/011/002/031 15.2 B100138 AUTHOR: Belov, K. P. N~ -- TITLE: The effect of the magnetic sublattice structure of ferrites on their physical properties PERIODICALi Akademiya nauk SSSR. Izvestiya. Seriya fizicheskaya, v. 25, no. 11, ig6i, 1320-1326 TEXT: It is well established that the structure of ferrites exhibits magnetic sublattices. When a composition has what is known ass. oompensation point.Q., the sublattices not only cause the magnetic characteristics to behave peculiarly around Qc, but also, at low temperatures anomalies in physical properties. The 8-uthor studied the low-temperature anomalies of ferrites having a compensation point. The behavior of such ferrites in the range of nitrogen temperature was found to be similar to that at the ferro magnetic Curie point. To explain the reasons of the anomalies the garnet- type ferrite d34-j(Pe3+)' e3+10 is considered. This ferrite may be ~G 3 3 IF 2 12 regarded as consisting of two sublattices. In order to study the iron Card 114s- 30058 S/048/61/025/011/002/031 The effect of tbe magnetic sublattice ... B108/B138 eublattice separately from the gadolinium sublattice one has to substitute 3+ 3+ 3+ the G ions by.nonmagnetic ions, e.g,, Y or.Lu . Where the temperature dependence of the spontaneous magnetization of such a ferrite, for instance yttrium ferrite garnet,.is known one may estimate the temperature .dependence of the spontaneous magneUzation of the gadolinium sublattice, by comparing the gadolinium ferrite curves with the corresponding curves of the iron sublattice in, say, the yttrium ferrite, The anomalies of the gadolinium ferrite near IOOOK are due to the fact that the weak positive interaction in the gadolinium sublattice ceases at low temperatures leaving only the negative Gd3+ -Fe3+ exchange interaction. Lithium ferrite chromites with a go exhibit.the same behavior. The iron sublattice shows the normal Weissian temperature dependence of spontaneous magnetization. Owing to the different exchange interactions of the sublattices, the physical properties of a ferrite are diff6rent above and below 0. and show strong anomalies near Gc(Fig. 6). The appearance of a 0. at low tempera- tures is due to the sublattices. The sublattice with the greater magnetic moment(virtually~ at OOK),and weak exchange interact4on shows no sharp time dependence ef spontaneous magnetization, the one with the smaller Card 2/ X15 58 __R10481 1 025/011/002/031 The effect of',the magnetic sublattice..* B10~/'B138 .magnetic moment shows aweaker-exchEinge interaction and a.Weissian shaped spontaneous-magnetization curve. This papei was read at the Conference on ferromagnetism and anti ferroma&metism in Leningrad, May 5-11, 1961. Mention is.made of A. N. Goryaga,.Lin.Chang_ ta (Zh. eksperim. i teor. fiz., Al- 6q6.(1961)) and L. A. 'Malev3kaya.(see Association entry). There are 7 figures and 4 references; 1,3 Soviet and.1 non-Soviet. -ASSOCIATION: Pizicheskiy fakul'Itet Moskovskogo gos.,universiteta im. 14~-V. Lomonosova ( Department of Physics of Moscow State University imeni M. V. Lomonosov) Fig. 6. Anomaly of physical,properties of gaAolinium ferrite-garnet at low temperatures and near Q.. Legend: 0 stands for 9 paraprocess c`Xn susceptibilityt magnetic susceptibility, Ho -,coercive force, AH width of the ferromagnetic resonance absorption curve, a spontaneous. on E Young's modulus, q. internal friction, magnetiZati (1) E, Card 3//?. -k~7 1 30068 111-14 S/048/61/025/011/013/031 -)%j B104/B102 AUI-"'HORS: Belov, K. P., and Malevskaya, Lo A. TITLE: Magnetic and resonance properties of_yttrium ferrite garnets when substituting 71011 Nd5+9 and Lu)+ ions for y3+ ions PERTODICALt Akademiya nauk SSSR. Icvestiya. Seriya fizicheskaya, v. 25,- no. 11, '1961, 137.1 - 1375 TEXT: The authors studied the effect of the magnetic sublattice structure- upon the magnetic properties of ferrites. 'For this purpose, they examined the magnetic and resonance properties of yttrium fer--ite garnets, in which the yttrium ions were replaced partly or entirely by terbium, neodymium, or lu#tecium ions. The spontaneous magnetization of the ferrite garnets (3-X)Y 203' xTb 2.03'5Fe2031 is shown in FIig. 1 as a function of temperature. As may be seen (curves I and 2), these curves are abnormal. Ifthe Tb ,content is increased, a compensation point of the magnetic moments of the sublattices appears (curve 3). According to a calculation by Niel's scheme, this point should be near OOK. Rare-earth impurities are probably respon- sible for its shift to 10OKo On further increase of the Tb content, the Card 1/4 30068 S/048/61/025/011/013/031 Magnetic and resonance properties... B104/B102 COMDensation point is further shifted to higher temperatures (curve 4). At low temperatures, a sharp increase of the coercive force He is observed as the Tb content rises. The vicinity of the compensation point is supposed to be the cause of this. J. Dillon (Phyzq~ Rev~q ill, 6 (1958)) and -the authors (Zh. eksperim. i teoret. fiz., 40, no. 2, 711, (1961)) showed both experimentally and theoretically that the resonance line width LH paSses through a maximum when minute Tb amounts are added to the ferrite. With an increase of the Tb content, the temperature anomaly of AH widens as a function of temperature. At verylow temperatures (20K), AH is not diminisk*i, This is explained by the fact that at low temperatures the AH broadening is caused not only by the Kittel-Dillon mechanism but also by the het-trogeneous .magnetic state due to the vicinity of the compensation point, The polycry- stalline Y-Nd ferrites (3,-x)y2o 3' xNd20 OFe2o3were of garnet structure with x < 21 The lattice periods 0f these garnets increased with incre6sing Nd content, from 12.37 R OY20OFe2o 3) to 12~50 R (Y20 3' 2Nd2O 3' 5Fe 203 ). When Y3-& ions were completely replaced byNd3+ ions, the resulting spe.;imens had a perovskite structured In agreement with Ne'el, the magnetic moment3 of ferrite garnets at absolute zero were found to be 6-5 - r-1Gr-(16d--4WA)- Card 2/k C 0 30068 3/048/61/025/011/013/031 Magnetic and resonance rroperties ... B100102 a n d -_~'aare the magnetic moments of the sublattices. Near absolute zero, saturation magnetization diverged from the values calculated by Nbel. MAsis explained in that the magnetic moments of Nd3+ ion3 do not attain any ferromagnetic order in the sublattices, as excharige interaction is insuf- ficient. In the ferrites (5-x)y 0 xLu 0 5Fe 0 the magnetic moments did 2 3 2 3 2 3 not change with x. The weak change of the Curie temperature (-,100) ob- served may be due to the change of lattice parameters. Structural inhomo- geneities arise due to the smaller radius oi7 Lu ions, and in their turn give rise to magnetic inhomogeneities. In,these ferrite tystems magnetic viscosity effects have been discqve ed; ' Y-Tb ferritest q-600K~, 00 oe, r relaxation time of magnetization riesponset 5-- 10 min. Y-Nd ferrites: 4.20K, 4000 oe, 30 - 40 min. Y-.Lu ferrites: viscosity'at 4.20K, due to structure. There are A figures and 8 references: 3 Soviet and 5 non- Soviet. The three most recent reforences to I-nglish-language publications read as follows: Kittel G., Portis A.,'de Gennes P., Phys. Rev., 116, no. 2, X23, (1959); Dillon J., Phys. Rev., 111, 6 (1958) White R., J . ApTyl. Phys., 32, 11780961). Card.3/0 300q1 S/048/61/025/011/0-i6/031 12 4 -1 V) ID (41.eo 1144) B100102 AUTHORS: Belov,jL--P., Levitin, R. Z., and Nikitin, S. A. TITLEt Magnetoelastic properties of terbium and holmium PERIODICAL: Akademiya nauk SSSR. Izvestiya. Seriya fizicheskaya', v. 25, no. 11, 1961, 1382 - 1364 TEXT: The temperature dependences of the magnetic properties of Dy, Tbq Tu, Er, and Gd have a complex character. While being ferromagnetic at low temperatures, they pass over, at a specific temperature 01,into the anti- ferromagnetic state with the Curie temperature 02. The antiferromagnetic state between 0 1 and G2 can be easily destroyed by an outer magnetic field. For Tb 0, - 2230K and '92 %2340K. Thi antiferromagnetic is destroyed b .y a field of about 200 oersteds. Below 230 0K the modulus of elasticit E dii- plays a strong anomaly and the inner friction has a maximum at 2234 .(Fig. 1). At the temperatures 9 2 and 0, this anomaly passes through a, maximum and a minimumt respectively. Longitudinal and transverse magneto- striction of Tb were measured at different temperatures as a function of the Card 1A~L, 30071 S/048/61/025/011/016/031 Magnetoelastic properties of..* B104/BI02 fi eld strength Ow750-10- 6 at 15 koe). The temperature dependence of the modulus of elasticity and of internal friction of Ho was examined near 1960K only (Fig. 3). The shear modulus, too, is anomalous in Ho~ This proves that not only a pure bulk deformation occurs with the 0 2 trans ition. As for Dy, it isknown that below the axial ratio of th e -6 unit cell changes ;L--1000-10 at 15 koe. Neutron diffraction studies showed that Dy in the.antiferromagnetic.range (above 01 ) has a so-called helicoldal spin structure: the spinsare heliooidally arrang~-d in.the lattice. It is believed that other rare-earth metalsi particularly Ho and Tb, also possess this spin structure. There are 3 figures and 6 references: 3 Soviet and 3 non-Soviet. The three references to English-language ~publications read as follows; Thoburn W.i Legvold,S., Spedding F., Phys. --Rev., 112, 56,0958)v Bamistar'I.~R~j .-Leg,old~S.O'Spedding F., Phys- Rev., 9-40 1140 (1954); Koehler W.g Wollan E., Lecture delivered at a seminary on rare earths elements, USA# California'-p October 1960. ASSOCIATION; Fizicheskiy fakulltet Moskovskogo gos, universiteta im. M. V. Lomonosova (Physics Division of Moscow State University imeni Card 21k1h M. V. Lomonosov) 12 D AUTHORS: 11-1~'j 1 30073 3/046/61/025/011/019/031 B117/B102 TITLE: Belov, K. P., Zaytseva, M. A., Kadomtseva, A. M., and T71-m-o-f-eyeva, V. A. Magnetic anisotropy and-hysteresis properties of rare-earth orthoferrites PERIODICAL: Akademiya nauk SSSR. Izvestiya. Seriya fizicheskaya, v. 25, no. 11, 1961, 1389-1392 TEXT: Magnetic anisotropy was examined on single crystals of La, Pr, Nd, Sm# Eu, Gd, and Yb orthoferrites. The crystals were grown by spontaneous crystallization from thqir -solution in a meltof lead compounds, lead oxide, and lead fluoride. The torque of the resulting crystals as a func- tion of their angle o:! rotation with respect to an external magnetic field of up to 20 koe was moasured with an anisometer. The torque curves drawn at room temperature resembled one another in the examined singlti crystals, and showed that the orientation of the magnetic moment in the aNir3 of easiest magnetization is very stable against rotation of the outer field. This points to an exceediiigly strong magnetic anisotropy of these Card 1 /,k 15 Magnetic anisotropy and 30073 S/048/61/025/011/019/031 B117/B102 orthoferrites. If the temperature is increased to the Curie point, the anisotropy of weak ferromagnetiam is virtually not reduced. The characteristic phenomena of hysteresis and thermal remanence effects, appearing.in rare-earth orthoferrites can be explained also by the strong magnetic anisotropy. Thermal remanence phenomena were observed on polycrystallire La, Pr, and Yb orthosilicates (Ref, 5: Belov, K. P_ Zaytseva, 111. A., Kaclomtseva, A. !.1. , Zh. eksperim. J, teor, fi::, i't e f . 6: ',.Yatanabe, 11. J, Phys. Soc, Tapan,. '14, 511 ~'agnetization curves and hysteresis loops were recorded in magnetic fields ., I of up to 20,000 oe by a pondermotive method. Specimens cooled in the magnetic field displayed asymmetric hysteresis loops with indIvIdual. cycles. The thermai remanence was removed by a magnetic field -f the order of 10,000 oe, This is indicative of the enormous coercive force of these orthoferrites. A partial substitution of nonmaenetic A13t- ions for Pe3+ ions was performed in polycrystalline La and Pr orthoferrites~ A shar v diminution of both coercive force and thermal remanence vhenomena was observedalong with a steep rise of magnetization. The latter may be explained by a prevailing diminution of the exchange field. On the cther hand, the growth of magnetization is possibly associated with the greater Card 21~7 30073 S/048J61/025/011/019/031 Magnetic anisotropy and B117/B102 3+ difference in the magnetization of the two sublattices of Fe ions, when they are partly replaced by nonmagnetic A13+ ions. However, the Curie point is lowered in every case. Compositions in which Fe3+ ions were partly replaced by magnetic Cr3+ ions were examined. As compared with stoichiometric compositions I the coercive force diminishes sharply in La and Pr orthoferrites, when Cr3+ ions are introduced. As expected, and unlike A13+ ions, cr3+ ions do not change magnetiza tion very much. The Debye diagrams taken by A. A. Katonellson and K. Yatskullyan showed that all the examined compositions are solid solutions without any foreign phase. Ye. A. Turov is thanked for his help and for having discussed the results obtained. V. A. Kaysh (Fizika metallov i metallovedeniye, 1, 10 (196o); 11, 161 (1960)) is mentioned. There are 5 figures and 6 refer- ences: T-Soviet and 4 non-Soviet. The three references to English- language publications read as follows: 3ozorth, R. M., Phys. Rev. Letters, 1, 362 (1958); Gilleo, 11. A., J. Chem. Phys. 2A, 1239 (1956); Watanabe, H., J. Phys. Soc. Japan, 14, 511 (1959). Card 3 S104 f 25/012/001/622 13 B137 'AUTHORS: 'Belov, K P. d~_Zalesski A. V. an TITLE: Variation of resistivity on magnetization and the magnetic anisotropy of Mn xFe 3-x04 ferrite single crystals PERIODICAL: Akademiya nauk SSSR. Izveatiya. Seriya fizicheskaya, v. 25, no. 12, 1961, 1434-1436 TEXT: The anisotropy constant K 1 of solid solutions of magnetite and manganese ferrite (Mn x Fe 3-x0 4) is positive only in the range 0.6< x< 0.8 at room temperature. This can be attributed to the change in ion distribution on transition from the inverted spinel (magnetite) to the* normal one (manganese ferrite). The magnetite has the magnetostriotion constants X - -19-10- 6 and 81-10-6 1 and the manganese ferrite 100 -6 6 MnO.98F,l .8604 has the constants 1100 --14'10 and Xill - -I-10- . On transition from the manganese ferrite to themagnetite, the magneto- Card 1/4 S/048 61/025/012/001/022 Variation of resistivity on... IB137 B108 striotion along the [111] axis change3 its sign. According to A. Braginskiy (Chekhosl. fiz. zh.p 2, no. 6, 755 (1959)), this change is observable in the range 1.00) r,,q and both are nags- -tive 0 need not, in the range T > G0 r1) becomes po.sitivet the point r1, coincide with 000 Inthe range of-the Curie point, the negative maxi- mum of the galvanomagnetic paraprocess.is somewhat greater for rj. than ~'for rV. This is due to.the fact that the difference between r L and rl, does not completely;dioappear at the Curie point. The experimental re- sults prove that in (A) sublattices exist with different tempere:ture de- pendence of spontaneous magnetisation. There are 5 figures and 3 re - ferences; 2 Soviet-bloc and I non-Sov'ist-bloce t ASSOPIATIONt Moskovskiy goe'udars vemW universitet'. (moseow'State'rniversity) SUBMITTED r October 11, 1960 Carl .316,'~ 25182 8/056/61/040/006/003/031 BI02/B214 '7 AUTHOhSt Belovo K. P., Leviting BeZop Nikitinj S. A.p Ped1kop A, V, TITLE: The magnetic and magneto-elastic properties of dysprosium and gadolinium PERIODICALt Zhurnal eksperimentallnoy i teoreticheskoy fiziki, v. 40, no. 69,1961, 1562 - 1569 TEXT: The interest that is being recently taken in the study of the magnetic properties of rare earths and their alloys is due to the follow- ing two causess al In some rare earth me.tals (Dy. Hot Er, Tb, Tu) there occur complicated magnetic transformationn from ferro magnetic to anti- ferromagnetic and then to-the paramagnetic; b) in some rar? earths there are uncompensated electron spins in a'shell which is screened by outer 5s and 5P electrcns~ For this reason "he direct-exchange'interaction be- tween the 4f electrons is very difficult or even impossible. The authors have carried out measurements with tbegreatest possible accuracy on magnet- iz ation, magnetostriction,~,, elastic modulus E, and the inner friction Card 1/ 25182 6/056/61/040/006/003/031 The magnetic and magneto-elastic proper- B102/B214 ties of of Dy and Gd and obtained them as functi one of temperature. The pre- sent paper is concerned with the results of these experiments. The meas- urements were carried near the points 0 1 and 92 and in the region between them (91 is the.temperature of the ferromagnetio - antiferromagnetic tran- sitiong and 92 that of the antiferromagnetic paramagnetic transition). The results of the investigations are represented graphically. For Dyj 01 was found to be 88 0K and 0 1750K. The character of the anomalies of E 2 an d for Dy at Q2 is the same as in the antiferromagnetic Cr2e3t i. e. 02 is the Neel point. The behavior near 0 1 is entirely differenti The magnetic field has a strong effect on the Young's modulus E (A E effect) as well as on Q71 the changes of these quantities being irreversible. Card 2/ 9MOMMOMMM 25182 S/056/61/040/006/003/031 The magnetic and. magne.to-elastic proper- B102/B214 ties of This means hystereses. These are shown for AE and Q_ I for 85 0 X in Figs. 2 and 3. All this signifies that,Q I is not a phase transition point of the Becond kind, and is in no way related to structural transformations. Pig. 4 shows the temperature dependenoe of Dy which shows particular peculiari- ties near Q . Firstly, the magnetostriction at this point is unusually 'high (10-3al 15vOOO oe), and secondly, it is anisotropic. Moreover, there is for each temperature a. critical value Hkat which a sudden rise of A begins. Gadolinium whose ferremagn6tism was discovered early has always been considered as a "normal', fe.rrcmagnetica However, the authors have 'discovered that in weak fields there are anomalies in the temperature be- havior of magnetL-ttion (Fig. 6), aoercive force H. (Fig. -1), and residual magnetization (Pig. 8). It may thus be concluded that a tem 8erature .exists for Gd (simillar to the 2170C point for Ni and tbe 294 C point for CO) at which a temperature anomaly of ~ and H C exists. Contrary$ howeverv to Ni.and Co~ Gd shows two aingularities in the behavior of magnetic prop- erties near the Curie point (0-290-5'K)o The curvature of the curve show- Card 311Y 25132 S/056/61/040/006/003/031 The magnetic and magneto-elastic proper- B102/B214 ties of -Ing.the decrease of magneti2ati.on with temperature is very small and can be deter-ined from the formula; For Ni and Fe S-6 - 7; for Gds 1.170 Such a small value is characteristic of ferrite and some alloys (cf. Table). The existence of anomalous behavior of Od (as compared to Ni and,Fe) near 0 is due to the presence of an antiferromagnet- ic phase in this region of temperature, which, however, can be destroyed by weak fields, The authors thank Professor Ye. M. Savitskiyj V. F. Terekhova and 1. V. Burov for preparing the Gd sample and A. S. Borovik- Romanov for discussions. There are 12 figurest 1 table, and 12 references: 4 Soviet-bloc and 8 non-Soviet-bloc. The most important references to English-language publications read as followsi J. Elliot et al.-Phys. Reir. 2At 1143, 1954; D. Behrendt et al. Phys. Rev. 109, 1544, 1958. ASSOCIATION: Moskovskiy gosudar8tvennyy universitet (Moscow State Univer-i sity) Card 4/ 28749 1.3/056/61/041/003/002/020 At 7 116 B125/B102 AUTHORt Belov, K. P. TITLEt The nature of low-temperature magnetic anomalies in ferrites possessing compensation points PERIODICALt Zhurnal skeperimentalinoy i teoretioheskoy fizikil V, 4 19 no* 3(9), 1961t 692 - 695 TEXTs The author shows that, at liquid-nitrogen and liquid-helium temper- aturest a critical point occurs in the temperature'dependences of the magnetic and non-magnetio properties (magnetic ausoeptibility, magnet- ostriotion, coercive force, electric resistivi ty) of rare-earth ferrite garnets and of lithium ohromite ferrite. The compensation point of 3 Gd20 3* 5PO20 3ferrite is studied. To find the -cr(T) curve of the iron- a sublattioe, it is necessary to eliminate the magnetic effect of the gadolinium sublatticep ioeo all Gd3+ ions must be replaced by non-magnetic ioIns (00 g..y3+ or Ln3+)* The resulting ferrites 3Y20 3~5Fe2O 3 or Card 1/~ 28749 S/056/61/041/003/002/020 The nature oflow-temperatursos* B125/B102 7L- AU2 O,*5Fe203 show the normal Weiss temperature dependenee of spontaheous. 0 magnetization. Their magnetic long-range order is destroyed only at 560 KI owing to the strong interaction in the iron sublattioss The temperature dependences of the-spontaneous magnotization of the gadd1inim sublattico and of some alloys (*. g. 30A cut 70~ NO are not distinct. Probably# this is due to the fact that the ling-range magnetic order in the gadallnium sublattioe ttepende on the positive Od + exchange interaction in the sublattioe op and on the negative Gd3+ . re 3+ exchange inte'raction. The long-range magnetic order undergoes a considerable change when the'positive exchange intoraotion is "turned off" with rising temperature, but the negative exchange interaction prevents its complete destruction. All these facts lead to the, condition under which the compensation point in ferrites is the most probable to occur. in the ferrite, one of the aublattices must exhibit * strong exchange interaotiong and the curve de (T) mue .t consequently show * Weiss character. The exchange interaction in the second sublattioe must be "weak". The compenB ation point is found by subtracting curve I (with the smaller magnetic moment at OOK) from curve 2 which corresponds to the sub- Oard 2/5 28749 4/056/61/041/003/002/020 The nature of low-temperatureeo. B125/B102 lattice with the greater.magnetic moment at 00K (Fig.2). If the magnetic moment of the "weak." sublattice at OOK is smaller than that of the "strong" sublattice, G' (T) of the ferrite will be anomal at low temperatures. a 3+ Similar ourves.oan'be observed in yttrium ferrite when part of the Y ions 3+ 3+ are substituted by,Tbl , Od or other ions'D Lithium chromite ferrite of the composition Li 0-5 Fe 2-5-a Cr a04(for a - 1.25) for instance has two antiferromagnetically interacting sublattices, the first containing Fe3+# Cr3 + and Li 1+- ions.(ootahedra-I sites), and the second containing Fe3+ and Li 1+ ions (tetrahedral sites). At,low temperaturesp the ferroma gnetism of the ferrite depends on the octahedral sublattice. According to L. Neel (Ann, de Physique, 3-, 137i 1948), the - a (T) curve exhibiting the compea- sation point can also be found from the a sB (T) and -a sA (T) curves of the ,octahedral and tetrahedral sublattices, respeetiYely, which exhibit Weise character. Ferrites with a compensation temperature must have a low-temper- ature'p`Oint which'coir"responds to a considerable change of the magnetic Card 3/5 2870 8/056/61/04-1/003/002/020 The;na,ture oflow-temperature.i,, B125/B102 long-s-r-ange order in a sublattice with "weak" positive exe hange interactions According to A. V. Pedlko (ZhETP, tj, 31 700), the anomalies of the temper- ature aepe'ndenoe of the susceptibility of the para-procossest.of the magAetos.triotion and of other phenomena are simiLar to the anomalies at the Curie.,point,- A.. N.-Goryaga and Lin Chang-ta (ZhETFj,.419 3, 696) diecuseed anoiiiies in *th~ temperature',dependence of spontaneous,magnetizationg of the coer~iv~,'-torce,.,?f.magnet~io, susceptibility of the gal vano -magnetic effect, ifid of the ~1*ectrio'resistivity. There are 2 fi'gures and 7 referencest 4-Sov-1st and 4 non-Soviet. The two references to English-language publications read as follows: E. Lee, R. Birss, Proc. Phys. Soo*, 2-6, 411, 1960; E* W. Gorter. Phil. Res* Repo, 2, 295, 1954o ASSOCiATIONs Moskovskiy gosudarstvennyy universitet (Moscow state University) SUBMITTED: April 6, 1961 Cara 4/5 U141 -8/181/62/004/010/028/003 B108IB104 AUTHORS: Belov,-K. P., Svirinap Ye. P.j -an~. Malikova, 0. A. TITLE: The electrical conductivity of manganese ferrite single crystals PERIODICAL, Fizika tverdogo tela) v. 4, no. 10, 1962, 2629-2631 TEM, The temperature dependence of.the Hall emf, of the magnetization 6, and of the el,ectrical conductivity I/Q of manganese ferrite single crystals was studied. The crystals were slightly out of the stoichiometric c4pmposition 'either by a manganese or by an ixon excess. The Hall emf V E.I. (R H +' 6)j increases rapidly with an excess of Un. The magnptic Hall 0 ~constant R rises linearly with increasing-Q. The classicai Hall conatani m R0 is negative. The electron concentration calculated from it increases with increasing temperature according to an exp;n;ntial law. The'electron mobility calculated from R 'and Q,decreases coniiderably with increasing 0 temperature in the-case of manganese ferrite with excess Un. In ferrite Card 1/2 S/1'el/62/004/010/028/063 The*electrioal conductivitylot... If 00104 n. with excess Fe it decreasesnonly a litzle. Thiq shows that in the former case the phonons contribute most to the scattering,of electrons (A.Miller. -J. Appl. Ph~s.y 319 no. 5, ~61., 1960). There 4fe'5 figures. 1 ASSOCIATION: Moskovskiy gosu4ar'stve.nnyy univerriitet im. M. V. Lomonosova (Moscow State University imeni Mq-V. Lomonosov) SJBMITTED: May 26, 1962. Card 2/2 5/07o/62/007/002/008/022 It, 0 E132/El6o AUTHORS: 1jelov, K.P.s Zaytsevaj M.A.* Kadomtsevaj A.Me, and Ovchinnikova, T.L. Kvitkaj S.S., TITLE: The'magnetic properties and structures of certain garnet systeRs PERIODICAL: Kristallografiya, v-7, no.2, 1962, 242-246 TEXT: Garnet structures have been synthesized by the substitution in yttrium iron garnets of Fe and Y ions by,?-!no Ge_ and Ti and their structures and magnetic properties have been studied. In the garnet of composition Mn 0.5 Y2.5 Fej,.5GeO -5012 an anomalous temperature dependence of the spontaneous magnetisation has been observed at low temperatures (of Neelks type M). It is established that the garnet of composition MnY 2Fe4GeO.2 has a Curie point below 0 OC and that the curve of ,the temperature dependence of the spontaneous magn*tisation tends asymptotically to zero. The curves are explained-qualitatively. The cell size of the first-mentioned 6ompound is 12-367 1, and Card 1/2 The magnetic-properties and structures. S/070/62/007/002/008/022 'E132/El6o that of the second 12.347 as compared with 12-387 for the pure Y Fe garnet. In garnet there are three magnetic sub-lattices and on Neel's model M the curve observed for the first composition can bd satisfactorily explained if the-lattice having a weak inherent exchange interaction takes.a different course from that Pf the other (iron) sublattices. The Ti-containing garnets Mn 0.5Y2.5FO4.5 Tio .5012 and MnY.Fe4Tio,2 were examined but showed no anomalies except that the second compound had a "tail" of residual magnetisation which persisted above the Curie point (3o6 OC) apparently connected with the appearance of another phase (traces of Y Ti 0 were observed in the X-ray powder 2 2 7 photograph). There are 4 figures. ASSOCIATION: Moskovskiy gosudarstvennyy universitet im. M.V.'Lomonosova (Moscow State University imeni. I-1.V. Lomonosov) SUBMITTED: June 27, 1961 Card 2/2 S/126/62/013/001/001/018 E039/E535 AUTHORS: Belov, KyPe and Nikitin,.S.A. TITLE: The galvanomagnetic properties of terbium, dysprosium and holmium PERIODICAL: Fizilca-metallov i nictallovedeniye, v.1- 11o.1, 1962, 43-48 TEXT: Measurements of magnetic moment show that the rare earth metals have transition temperatures G for antiferromagnet',11. 2 paramagnetic and f.or-ferromagnetic-antiferroinagnetic. Hence,- the influence on electrical properties of the transition from a state of.non-ordered spin to an ordered one can be studi4~d on these metals. values of e and (9 originally published'by-. 1 2 S. Legvold, F. Spedding et,-al., are: Table 2 Element OK K E? 2' Dy 85 178.5 Tb 219 229 CarId 1/3 Ho 20 133 The galvanomagnetic properties S/126/62/013/001/001/018 E039/E535 Measurements of electrical and galvanomagnetie properties were made on samples of Dy, Tb and Ho (0.4 x 1 x 9 twit and 0.4 x 2.2 x 20 mm). Electrical resistance was measured ovet- the temperature range 60-3000K using a potentiometric method, a constant current of 100 mA being passed through the sample. It is 1- shown that there is a discontinuity in the resistaiice-tempernture.~. curves at 0- The temperature dependence of the longitudiiial and. 2 transverse galvanomagnetic effect was measured for.Dy, Ho and Tb for magnetic fields up to 15000 Oe and it is shown that the. galvanomagnetic effect passes through a mnrked negative maxinium near In' addition, in the case of Dy a second maxiinum is 2' observed at (-'1, 6The transition temperatures and for TI) are very close together, 219 and 2290K, respectively, so that only one,,.,,:, maximum is'obtained. Isotherms are plotted showing the change in longitudinal and transverse galvanomagnetic effect with intensit Y of magnetic field for a. number of temperatures. It is shown that the temperature dependence of the slope of the isotherm !~R/RZNH for Tb exhibits two inaxima at.2320K and 224uK. Thi-3 verifies the assumption that Tb.possesses-,Weak antiferromagnetic properties Card 2/3, 33999 S/056 62/042/001/614/048 B104/~102 AUTHORS: Belov, K. P., Ped1ko, A. V. TITLE: 'Helical" antiferromagnetism of gadolinium PERIODICAL: Zhurnal eksperimentallnoy i teoreticheskoy fiziki, v. 42, no. 1, 1962, 87-90 TEXT: The mEgnetic properties of polyarystalline toroidal specimens of gadolinium in magnetic fields between 0.28 and 2000 oe were investigated between 100 and 3000K. At 2100K, the specific magnetization drops sharply between 0.28 and 1.12 oe (Fig. 1). The curves have a normal Weiss shape only in strong fields (500-2000 oe). The magnetization isotherms between 01 _2100K and the Curie point 92 - 2900K were examined. Like the other rare-,earth metals (DY, Th, Ho, Er, and Tu), gadolinium exhibits two magnetic transitions at 9 1 and 92 and is antiferromagnetic between these temperatures. Antiferromagnetism vanishes already -in weak fields. The magnetic properties in this temperature range can be attributed to a helical spin structure. Suoh structures form when Card 33999 S/056/62/042/001/014/048 "Helical" antiferromagnetism of... B100102 the exchange interaction between the atoms of a layer of the basal plane of the hexagonal Gd crystal is weak compared with the exchange interaction between the atoms of contiguous layers. Application of magnetic fields of 0-15 oe destroys this struoture. There are 5 figures and 4 references: 1 Soviet and 3 non-Soviet. The three references to English-language publications read as follows: F..Spedding et al.9 Phys. Rev., 109, 1544, 1958; 2A9 1143f 1954; 1091 1547P 1958; 11-2, 56, 1958; 100, 1595, 1955; M. Wilkinson, W. Koehler, E. Wollant A. J'able. J. Appl0 Phys.0 12, 48, 49t ~SuPP1- to no. 3); U.-Enz. J. Appl. Phys., .32, 22 1961 (Suppl. to 1961 1 no. ASSOCIATION: Moskovskiy gosudaretvennyy univeraitet (Moscow state University) SUBMITTED* August 4, 1961 Fig. 1. Magnetization of Gd in weak and strong fields as a function of temperature. Card 21~_ S/056/62/042/002/016/055 B102/B138 AUTHORB; Belovp K. P., Nikitin, S. A. TITLE: Effect of helicalmagnetio structure on the magnetostrictionce dysprosium PERIODICAL: Zhurnal eksperimentallnoy i teoreticheekoy fiziki, v. 42, no. 2, 1962, 403-407 TEXT: Dysprosium has two magnetic transformation temperatures: 01 (650K), at which the helical magnetic structure arises and 02 (1770K), at which ferromagnatiam of the basal planes vanishes, together with the helical magnetic structure. The lower temperature range has been studied previously (K. P. Belov et al. ZhETF, 40, 1562, 1961); it was found that below 01, where the Dy crystal is ferromagnetic, and also between 0 1 and 021 the considerable anisotropy of magnetostriction is due to spontaneous 0 magnetostriction. In continuation of these studies the range 120-190 K was here investigated. The magnetostriction observed on approaching 02 will be caused by other kinds of spontaneous magnetostriction. The measurements were made with polycrystalline specimens and in magnetic Card 1/0 5/056/62/042/002/016/055 Effect of helical magnetic ... B102/B138 fields in which the magnetic momenta remained in the basal planes during magnetization. Magnetostriction was measured with a wire strain gage. The isotherms of transverse (x.L) and longitudinal (X,,) magnetostriction between 0 and 15 koe were measured for several temperatures. It can be seen that for fields below critical, 4 1 is negative and X UPositive. The temperature dependencesof X 11 and X11 differ in shape, and their positions depend on whether H is stronger or weaker than H 't' This is due to the, cri fact that in this temperature range, besides magnetostriction corresponding to rotation of magnetic moments in the basal plane layers, there also exists a magnetostriction concomitant with destruction of the helical magnetic structure for H . H crit* Around Q2 an intense paraprocess .magnetostriction arises which is caused by exchange forces between atoms in adjacent basal planes. A. S. Borovik-Romanov is thanked for discussion& There are 5 figures and 6 references: 2 Soviet and 4 non-Soviet. The four references to English-language publications read as follows: D. Behrendt et al. Physo Rev. jO 1$ 15441 1958- M- Wilkinson at al. J. Appl. Phys. 12p 499 1961; suppl. to 3- U. Enz. J. Appl. Phys. L2, 22, 1961, suppl. to 3- Card 2/*-3 S/056 /62/042/002/016/055 -Effect of helical diagnetic B102/B138 J. Banieter et &I. Physs Rev. As 1140, 1954- ASSOCIAT,I011: Moskqvskiy gosudarstvennyy universitet (Moscow State 'University) SUBMITTED: September 141 1961 Fig..10 Isotherm of Al Pig. 2. Isotherm of X* Fig. 4- -Temperature dependence of X for'7500 oe (1) and 15 koe (2) Fig- 5. Temp erature dependence.of X for 7500 oe (i) and 15 koe (2) Card 3/# EELOV, K.P., daktor fiz.-matem.nauk; SMALOV, L.A., kand.fiz.-matem.nauk -------------- Symposium on ferromagnetism and forToelectricity at Leningrado Vest. AN SSSR 33 no 9:82-84 S 163. (MM 160) (Di;lectrio'p) (Forrom,agnatism) MES SION RR KAiIASIK, Vladimir Romanovich; BRIOV.-K.P. -,,-,,,,prof.p red.; KOZLOV, V.D., red.; RYDNIK, . . ea. (Pbysics and technology of strong magnetic fields] Fizika I tekbmika silIn7kh magmitnykh polei. Moskva, Neuka, 3964. 347 P. (MIRA 17:10) ACCESSION NR.- AP4911744 S/0181/64/006/001/0101/02.07 Werohovap V. I.; Zsytseva, AUTHORS: lo* X M. Aq Kadomt3evap A. Me; Y !,Katsnells Y on, S: takulfyaks K. T;TLE: Magnetic ar# structural properties of laAthanum orthoferrite during partiali. jwPlacemant of Fe ions by other trivalent ions .Pizika Wordogo t no."I,. 1964~ .101-107 olas ve 6,o TOPIC TAGS: =gne~tic propertyp structural property, ortho~errite., lanthanums lanthanum orthoferrite, Fe.34-..,Al 3+s $0'3'1) Cc -3*,, thermoremanant magnetization, ,,'magnetization intensity, hysteresis loop# crystal lattice -30 ABSTRA. the F94,3 I a*3 S 0*3 Cr4 R.-- In these studies on was replaced.. in part,, by J and Cc -~, Thermoromanentmagnetizatigq of LaFA cannot be reduced jo zero even im a field of 20 000 oersteds,, but if Al -2 ~ona re-;~ce some of the Fe ions 0.9 -110.10 introd4ced by orthorhombic distortion ofthe crystal latticep thez=- 3 rejo nerf-6,L#gnetizajion almost disappears, and the hysteresis loops become sy=etri-:. cal. These changei;may be explained by the finely dispersed character of the samples. The char4t!e in magnetic properties on substitution of the irAicated ions Card 1/2 176/64/017/004/0617/0610 AqCESSION NR s AP4034061 S/O ~BelQ_V,,,X*,_Paj_Levitinj R;* L; Malevskaya# Le Ael Sokoloyq Vo Is TITLEs Anomalies of Young's modulus in rare ear- fox vw4pets metalloireden4o` V- 17# no SOURCES Fizika metalloy i 4P 1964P 617-619 TOPIC TAGSs rare earthp ferromagnet, Young modulus, dysprosium# erbium, holninmt 'thuliump helicoidal ferromagnatio struaturej paramagaetism 1ABSTRLCTt Rare earth ferrom~aanete (3brp Frp Ito, Thp Tu, and possibly Od) at certaini temperature intervals possess antiferromagnetio helicoidal structures. To investi- asons for the formation of these etructurest the Young's modulus was gate the re I measured. at various'temperatures. A compound vibrator was used at a frequency of-I 150 kilocyoles/sec, and the temperature was changed continuously from 4-2 to 78K br 1 placing the specimen in a massive copper vessel which could be cooled down to a Itemperature near that of liquid helium. Further variation of temperature between 178 and 300K was obtained by using liquid nitrogen and an electric heater, The magnetization was measured by means of an oscillating magnetometero The results Ishowed three regions in which anomalous behavior of the Young's modulus could be I observeds 1) a region around which a transition took place from antiferromagnetion Card 0: !ACCESSICK NR: AP4023400 8/0048/64/1D28/003/0519/0528 I-AUITHOR., Belov,K.P.LLeV1tin,R.Z..; Nikitin,S.A.; PW ko,A. V. :TITLE: Uagnetoelastio properties of rare earth ferromagnetic materialaffeport. -!Symposium on Ferromagnetism, And rer electricity Isseld in Leningrad 30 gay 'to 6 %Tune a6v SOURCE: AN SSSR. ..Xzvestiya. Seriya f izicheskaya, v.28, no.3, 1964, 519.P-528 TOPIC TAGS - magnetostriction, rare earth magnotostriction, magnotoelasticity , rare earth magnetoelasticity, rare earth exchange anisotropy, helical antiferromagnetism ABSTRACT; The magnetostriction, the tcmperature dependence of the elastia.moduli, and tho effect of hydrostatic pressure on the magnetization, are discussed in some detail for a number of rare earths, The experimental data for the discussion are taken from a number of sources6 These magnetoelastic properties are of interest be-, cause they Involve a combinationof exchange and magnetic interactions, and their ;behavior may shad some light on the complex magnetic properties of these materialso' ~Xn the range.of temperatures and fields In which the materials are forromagneiia, magnetostriction can tant& of Dy and Th are.large, and the two constants (for I. Qrd 1/3 ACCESSION NR: AP4023400 'the same-material) are of' opposite sign. Th e magnetostriction is due primarily to !rotation of the:magnetic moment in the basal plane against magnetic anisotropy fo.-I I ces. The magnetostrictive behavior of Gd is very complex and is not understood. Ini ithe range of temperatures and fields in which Dy exhibits helical antiferromagnetisA ;its magnetostrictive behavior Is complex. A simple theqry of magnetos t ri ction is de"O voloped, in which the magnetic anisotropy in the basal plans is neglected (presumab,-~ a reasonable approximation in the temperature range considered) and the exchanged interactions between neighboring basal Olanes and between next-neighboring basal planes are assumed to be different linear functions of the strain in the hexagonal axis (i.e.; of the distance between the basal planes). This theory accounts quali- .tatiVely for the complex behavior observed. Unlike the behavior of magnotastriction in the iron group, the magnetostricvion of Dy and Th is nnisotrobic even very close, .to the Curie point..This indicates that the.exchange interaction In these materials; 'is anis.otropic. The anisotropy of the exchange interaction is also indicated by the i fact that, the ishear modulus of Dy has the same typo of anomaly at the Curie point as has Younglo. modulus, The terromagnatic-antiferromag3iotic transition point of Dy !'is shilted tollowerr temperatures by the application of hydrostatic pressures The .transition of 'Olycrystalline Od at 2100C behaves similarly. After a short thermo-'! I C.,d 2/3 :ACCESSION NR: AP4023400 ;.dynamic discussion it is concluded from this that the exchange interaction between -the basal planes(ise., along the hexagonal axis) depends sharply on distancee :This, and other properties of tho exchange interaction revealed by magnOtOOla3tic j ~bohavior, is not:*oasy to understand on the basis of currents theories, accordinff to iwhich the exchange interaction in these materials is indirect, via the conduction .-.1electrons andthe SS2 and 5p6 bands. Orig.art.has: 10 formulas and 6 figures. IASSOCIATION: Xosk6vskiy gosudarstvenny*y universitot (Moscow State Univeraity) -SUBUITTM-: 00 DATE ACQ: IOApr64 ENCL: 00 a SUB CODE: PH NR REF SOV: 007 OrHER: 014 Ccr~ 3/3 BELOV,--4,Z.,.;. KADOMTSEVA, A.M.; LEVITIN, R.Z. Magnetic susceptibility of orthoferrites of rare earth elements in strong magnetic fields. Zhur. eksp. i teor. fiz. 47 no.2:439-443 Ag 164. (MIRA 17.-10) 1. Moskovskiy gosudarstvannyy urnivGr3itlets -ii --and-d awn cladolin: -um- 99X"99'i.~ SU r ahd iiii"Ied 'at---1200C' e ~transverse and lonigWiditial ure 1. ~" ~ - e- - ;. ~_ -- 5- ~ . , . -- _- - - ~ -- 7- __CU Aa_ 6ili one__~_Oorr4mpond, -t, i4_ 4- 11 0- -egionHof --- kP L i o I curie point itself t-~290X)- and dUe-to.intrinsic magnetization, and er --an( -broaderf, - Ocate som6what below the Ciarle !point (-230-250K)e Aminimum.of the negative gall?anomagnetic of- t lonal maximum-- obbe In, t e kVdd b6l( Wthis temperature. single-crystal gadolinium ~ a- sliarp' difference was observed in the ,character of the galvantomagnatic effect cur7es parallel and perpen- dicular to the hexagonal a-As, and this is interpreted as being d,le to a helicoidal ferromagnetic structure. Orig. art. has: 5 figures. ;ASSOCIATIONt btoskovskiy-,gosudarstvenny*y uaiversitet _(liquCOV state n' e 3 ENCL: 00 ~j 7, t~-- n --, --t, -.-- ~- ~ " - -- - - p-, i, . : ! ~-, -1 ~: - , L- - - - - , - L - : I , - - - Z:~6 77 77W :,,7777 ~7.17777 7- 00 ITIA& So CODE: SS., at ]m RW Sov:, 003 OTI-M 003 BELOV K*P*j kand, takhno nauk zzzz-:.~~ Lighting of passenger cars. Zhe2, dor, transpe 46 no,7294-95 J1 .1 6A (MIRA 170) Aw &~=;U-5 %Art ESD g5 '9/6056/64/047/002/0439/0~43 ACCEMON tqvl 0 ~k#- K.r rAvitin, R. Z. ~AUTHOF4 P-4 -Ka ~~ev.a# e ic-suacep fe rites, !-TITM --Inve-sti4ati6n,,o:E-iiqi4-i~agn tibility ofortho r of raie earib ~iemanta in strJoncr magnetic fields SOURCEs Zh. ekaper. i toot. fiz., v.'-47, no. S. 1964, 439-443 XC A%IS fQtrlt6',:M&vaQtic lm~ic-etitibi' -R -N AP40436i3 ACCESSION4 ASSOCIATION:`.' Moakovekiy gosudars-tvanny*y univereitet (Moscow ACCE.SSICtl NRs AP4043613 01 Fig, -~PenOacc-:..o sp~l? lc iza PrFeOs, 6 NdFeO~, 7 - YbFc