TY - JOUR

T1 - Magnetocaloric effect in single crystal Nd2Co7

AU - Ilyn, M.

AU - Bartashevich, M. I.

AU - Andreev, A. V.

AU - Tereshina, E. A.

AU - Zhukova, V.

AU - Zhukov, A.

AU - Gonzalez, J.

N1 - The work has been supported by the Czech Science Foundation (Grant No. GACR 202/09/0339). The work has also been supported by the Spanish Ministry of Education under the Grant No. NAN2004-09203-C04, by Basque Government under Grant No. Saiotek S-PE09UN38, and by Basque Government and by EU under Grant No. DEVMAG-MIWIRTEC (MANUNET-2007-Basque-3).

PY - 2011/4/15

Y1 - 2011/4/15

N2 - Single-crystalline sample of Nd2Co7 (T-C 613 K) has been used to study "anisotropic" magnetocaloric effect (MCE), originated from field induced rotation of the magnetic moment from easy-to hard-magnetization direction. Anisotropy constants were estimated using measured magnetization isotherms within 200-320 K temperature range, which encompasses two spontaneous spin-reorientation phase transitions. These data allow us to calculate the magnetic entropy and "anisotropic" MCE using simple thermodynamic model. Thus obtained MCE was successfully compared with MCE calculated by means of the Maxwell relation. Main differences between "anisotropic" MCE and MCE concerned with magnetizing of ferromagnetic substances near their Curie temperatures have been revealed. In spite of rather low characteristic values (Delta S = -0.005 MJ/Km(3), Delta T = 0.4 K at 235 K and Delta S = 0.005 MJ/Km(3), Delta T = -0.44 K at 250 K on the field change of 1 T) observed in Nd2Co7, intrinsic properties of the "anisotropic" MCE were found to be rather good: it may be a flat function of temperature, rotation of the moment can be completed in the moderate fields, neither temperature nor field hysteresises has been observed. Furthermore, the peak values of the "anisotropic" MCE are not limited by equation restricting MCE in the common ferromagnetic materials.

AB - Single-crystalline sample of Nd2Co7 (T-C 613 K) has been used to study "anisotropic" magnetocaloric effect (MCE), originated from field induced rotation of the magnetic moment from easy-to hard-magnetization direction. Anisotropy constants were estimated using measured magnetization isotherms within 200-320 K temperature range, which encompasses two spontaneous spin-reorientation phase transitions. These data allow us to calculate the magnetic entropy and "anisotropic" MCE using simple thermodynamic model. Thus obtained MCE was successfully compared with MCE calculated by means of the Maxwell relation. Main differences between "anisotropic" MCE and MCE concerned with magnetizing of ferromagnetic substances near their Curie temperatures have been revealed. In spite of rather low characteristic values (Delta S = -0.005 MJ/Km(3), Delta T = 0.4 K at 235 K and Delta S = 0.005 MJ/Km(3), Delta T = -0.44 K at 250 K on the field change of 1 T) observed in Nd2Co7, intrinsic properties of the "anisotropic" MCE were found to be rather good: it may be a flat function of temperature, rotation of the moment can be completed in the moderate fields, neither temperature nor field hysteresises has been observed. Furthermore, the peak values of the "anisotropic" MCE are not limited by equation restricting MCE in the common ferromagnetic materials.

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UR - http://www.scopus.com/inward/record.url?partnerID=8YFLogxK&scp=79955705333

U2 - 10.1063/1.3563583

DO - 10.1063/1.3563583

M3 - Article

VL - 109

SP - 083932

JO - Journal of Applied Physics

JF - Journal of Applied Physics

SN - 0021-8979

IS - 8

ER -