Correction of the shape effect on magnetic entropy change in ball milled Fe70Zr30 alloys

JOURNAL OF ALLOYS AND COMPOUNDS

卷:765

Article

Manchon-Gordon, A. F.¹  Ipus, J. J.¹  Moreno-Ramirez, L. M.¹  Blazquez, J. S.¹  Conde, C. F.¹  Franco, V¹  Conde, A.¹ 

[1] Univ Seville, Dept Fis Mat Condensada, ICMSE CSIC, POB 1065, E-41080 Seville, Spain

关键词: Magnetocaloric effect;    Mechanical alloying;    Amorphous alloys;   

DOI  :  10.1016/j.jallcom.2018.06.176

来源: Elsevier

【 摘 要 】

The field dependence of the magnetic entropy change (Delta S-M) after mechanical alloying of Fe70Zr30 composition starting from high purity powders is studied. Samples with different shapes and different crystalline fraction X were analyzed. Although the results show that the proposed correction of the demagnetizing field has not a significant effect on Delta S-M(T) curves (similar to 5% underestimation), it is necessary in order to properly analyze the field dependence of this magnitude (vertical bar Delta S-M vertical bar = aH(n)). This correction allows recovering the theoretically predicted field dependence as well as a deeper analysis on multiphase systems. In fact, the biphasic character of the studied system changes the value of the field exponent : it decreases below two above Curie temperature (T-C), and it increases at T-C. We show that, assuming a non-interacting phase model, it is possible to obtain the value of the exponent for the main phase from the intercept of n vs X/Delta S-M . (C) 2018 Elsevier B.V. All rights reserved.

【 授权许可】

Free