Magnetocaloric effect and inhomogeneity of CdCr sub(2)Se sub(4) and HgCr sub(2)Se sub(4) single crystals

Magnetocaloric effect in single crystals of spinels CdCr sub(2)Se sub(4) and HgCr sub(2)Se sub(4) is studied. The maximum value of the magnetic-field-induced change in entropy in the field of 15 kOe is about 1.4-1.5 J/(kg K). At Curie temperature the entropy change obeys the relation: -[Delta]S=[alp...

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Bibliographic Details
Published in:Journal of magnetism and magnetic materials 2015-08, Vol.387, p.127-130
Main Authors: Bebenin, N G, Zainullina, R I, Sukhorukov, Yu P
Format: Article
Language:English
Subjects:
Approximation
Curie temperature
Entropy
Inhomogeneity
Magnetic fields
Mathematical analysis
Single crystals
Spinel
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Summary:Magnetocaloric effect in single crystals of spinels CdCr sub(2)Se sub(4) and HgCr sub(2)Se sub(4) is studied. The maximum value of the magnetic-field-induced change in entropy in the field of 15 kOe is about 1.4-1.5 J/(kg K). At Curie temperature the entropy change obeys the relation: -[Delta]S=[alpha]H[2/3)-[beta]. The magnetic transitions in the spinels are found to be noticeably smeared. The experimental data have been compared with the theoretical results obtained for Heisenberg model in the mean field approximation (MFA). It is found that MFA overestimates the change of entropy in a magnetic field and underestimates the influence of inhomogeneity on [Delta]S.
ISSN:0304-8853
DOI:10.1016/j.jmmm.2015.03.093