Magnetic Phase Transitions and Magnetocaloric Effect in R2Fe17 (R = Y, Tb, Er)

The direct measurements of the magnetocaloric effect (MCE) and the magnetization for R2Fe17 (R = Y, Tb, Dy) compounds are reported. The maximal values of the MCE for different R2Fe17 compounds are almost the same at the Curie temperature and are equal to 0.8 – 0.85 K at ΛH = 13.5 kOe. The field dependencies of the magnetization and MCE and the dependence of MCE via magnetization deviates from the classical regularities and describes by the thermodynamic theory attracting the higher terms. Obviously the occurrence of the mixed exchange interactions in these compounds leads to the requirement of consideration both thermal and local fluctuations of the exchange integrals near the magnetic transition temperature.

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The Magnetic Phase Transitions and Magnetocaloric Effect in the Ho(Co1-XAlx)2 and Tb(Co1-XAlx)2 Compounds

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.168-169.119 ◽

2010 ◽

Vol 168-169 ◽

pp. 119-121 ◽

Cited By ~ 1

Author(s):

S.A. Nikitin ◽

G.A. Tskhadadze ◽

I.A. Ovchenkova ◽

D.A. Zhukova ◽

T.I. Ivanova

Keyword(s):

Phase Transitions ◽

Curie Temperature ◽

Magnetocaloric Effect ◽

Magnetic Phase ◽

Magnetic Ordering ◽

Magnetic Phase Transitions ◽

Al Content ◽

Direct Measurements ◽

Magnetic Ordering Temperature ◽

Ferrimagnetic Structure

Direct measurements of the magnetocaloric effect (MCE) and magnetization have been conducted for the R(Co1-xAlx)2 (R = Tb, Ho) compounds. It was found that the small substitutions of Co by nonmagnetic Al lead to an increase both of the magnetic ordering temperature and the value of MCE. The following increase in Al content decreases the Curie temperature and the value of MCE. The analyses of the MCE effect is conducted considering the ferrimagnetic structure and the itinerant nature of these compounds.

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Enhancement of the magnetocaloric effect and magnetic transition temperature in LaFe11.5Al1.5 by hydrogenation

Solid State Communications ◽

10.1016/j.ssc.2010.10.006 ◽

2010 ◽

Vol 150 (47-48) ◽

pp. 2329-2332 ◽

Cited By ~ 12

Author(s):

J.L. Zhao ◽

J. Shen ◽

B.G. Shen ◽

F.X. Hu ◽

J.R. Sun

Keyword(s):

Transition Temperature ◽

Magnetocaloric Effect ◽

Magnetic Transition ◽

Magnetic Transition Temperature

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Pressure effect on magnetic transition temperature and magnetic phase diagram of Mn2−xCoxSb

Journal of Applied Physics ◽

10.1063/1.348282 ◽

1991 ◽

Vol 69 (8) ◽

pp. 4642-4644 ◽

Cited By ~ 17

Author(s):

T. Kanomata ◽

Y. Hasebe ◽

T. Ito ◽

H. Yoshida ◽

T. Kaneko

Keyword(s):

Phase Diagram ◽

Transition Temperature ◽

Pressure Effect ◽

Magnetic Phase ◽

Magnetic Transition ◽

Magnetic Phase Diagram ◽

Magnetic Transition Temperature

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Effect of pressure on magnetic phase transitions of europium chalcogenides: EuO, EuS, and EuSe

Canadian Journal of Physics ◽

10.1139/p68-637 ◽

1968 ◽

Vol 46 (23) ◽

pp. 2703-2713 ◽

Cited By ~ 27

Author(s):

V. C. Srivastava ◽

R. Stevenson

Keyword(s):

Transition Temperature ◽

Magnetic Phase ◽

Exchange Interactions ◽

Theoretical Models ◽

Lattice Parameter ◽

Magnetic Phase Transitions ◽

Magnetic Exchange ◽

Effect Of Pressure ◽

Volume Dependence ◽

Magnetic Specific Heat

The effect of pressure on magnetic transitions of EuS and EuSe is reported up to 10 kbars. The compressibilities of EuO, EuS, and EuSe have been measured at 4.2, 82, and 300 °K for the same pressure range. The shift in the transition temperature of these materials has been measured through the mutual inductance of an astatic coil assembly containing the sample. Values of dTc/dP = +0.20 × 10−3 °K/bar for EuS and of dTN/dP = +0.16 × 10−3 °K/bar for EuSe have been obtained. Combining the compressibility measurements with dTc−N/dP the values of dTc−N/da = −290, −102, −68 °K/Å are obtained for EuO, EuS, and EuSe respectively, where a is the lattice parameter. These values of dTc/da for EuO and EuS are about three and two times the values derived from the plot of paramagnetic Curie temperature versus lattice parameter given by McGuire and Shafer. This difference is thought to be due to variations in covalency in going from oxide to selenide. For EuSe the value of dTN/da is in rough agreement with the value obtained by McGuire and Shafer. It is observed that volume dependence of magnetic exchange interactions in these solids deviates strongly from that of common superexchange materials; the magnetic Grüneisen constant is measured to be[Formula: see text]for EuO, EuS, and EuSe respectively. On the basis of recent theoretical models proposed for these materials, it is suggested that for EuS and EuSe the magnetic expansivity αmc should be proportional to the magnetic specific heat cm near the transition temperature according to the relation dTc/dP = 3TcVαmc/cm. The ratio αme/cm is estimated from the present measurements.

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Study of physical properties of a ferrimagnetic spinel Cu1.5Mn1.5O4: spin dynamics, magnetocaloric effect and critical behavior

RSC Advances ◽

10.1039/d1ra03732c ◽

2021 ◽

Vol 11 (41) ◽

pp. 25664-25676

Author(s):

Abir Hadded ◽

Jalel Massoudi ◽

Sirine Gharbi ◽

Essebti Dhahri ◽

A. Tozri ◽

...

Keyword(s):

Phase Transition ◽

Transition Temperature ◽

Physical Properties ◽

Magnetocaloric Effect ◽

Phase Transition Temperature ◽

Magnetic Phase Transition ◽

Critical Behavior ◽

Magnetic Phase ◽

Spin Dynamics ◽

Critical Behaviour

The present work reports a detailed study of the spin dynamics, magnetocaloric effect and critical behaviour near the magnetic phase transition temperature, of a ferrimagnetic spinel Cu1.5Mn1.5O4.

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