The isothermal variation of the entropy (ΔST) may be miscalculated from magnetization isotherms in some cases: MnAs and Gd5Ge2Si2 compounds as examples

JOURNAL OF ALLOYS AND COMPOUNDS

卷:509

Article

Carvalho, A. Magnus G.¹  Coelho, A. A.²  von Ranke, P. J.³  Alves, C. S.⁴ 

[1] Inst Nacl Metrol Normalizacao & Qualidade Ind INM, Div Metrol Mat DIMAT, BR-25250020 Duque De Caxias, RJ, Brazil

[2] Univ Estadual Campinas, UNICAMP, Inst Fis Gleb Wataghin, BR-13083970 Campinas, SP, Brazil

[3] Univ Estado Rio de Janeiro, Inst Fis, BR-20550013 Rio De Janeiro, Brazil

[4] Univ Estadual Maringa, Dept Engn Mecan, BR-87020900 Maringa, Parana, Brazil

关键词: Intermetallics;    Magnetocaloric effect;    Magnetic measurements;   

DOI  :  10.1016/j.jallcom.2010.12.088

来源: Elsevier

【 摘 要 】

The determination of the isothermal variation of the entropy (Delta S-T) is discussed in the present work We show that Delta S-T has very different profiles and magnitudes when calculated from M vs. H or M vs. T experimental data. For MnAs compound, Delta S-T A obtained from M vs. T data does not present a colossal peak This result and the agreement between theoretical and experimental non-colossal magnetocaloric effect indicate that the colossal peak may be miscalculated from M vs. H experimental data. For Gd5Ge2Si2 compound, Delta S-T obtained from M vs. T data does not present the peak observed in Delta S-T from M vs. H data. (c) 2011 Elsevier B.V. All rights reserved.

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