Tuesday, June 18, 2013

1306.3582 (Jianhui Xu et al.)

Large refrigerant capacity resulted from a wide temperature span of
entropy change in MnCo1-xFexSi

Jianhui Xu, Wenyun Yang, Qianheng Du, Yuanhua Xia, Xiaomin Liu, Honglin Du, Jinbo Yang, Changsheng Wang, Jiangzhi Han, Shunquan Liu, Yan Zhang, Yingchang Yang
The crystal structure and magnetic properties of MnCoxFe1-xSi (x=0-0.5) compounds was investigated. With increasing Fe content, the unit cell changes anisotropically and the magnetic property evolves gradually: Curie temperature decreases continuously, the first-order metamagnetic transition from a low-temperature helical antiferromagnetic state to a high-temperature ferromagnetic state disappears gradually and then a spin-glass-like transition and another antiferromagnetic state emerge in the low temperature region. The Curie transition leads to a moderate conventional entropy change. The metamagnetic transition not only yields a larger negative magnetocaloric effect at lower applied fields than in MnCoSi but also produces a very large temperature span (103 K for {\Delta}B=5 T) of {\Delta}S(T), which results in a large refrigerant capacity. These phenomena were explained in terms of crystal structure change and magnetoelastic coupling mechanism. The low-cost MnCo1-xFexSi compounds are promising candidates for near room temperature magnetic refrigeration applications because of the large isothermal entropy change and the wide working temperature span.
View original: http://arxiv.org/abs/1306.3582

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