Negative and positive magnetocaloric effect in Ni Fe Mn Ga alloy
Negative and positive magnetocaloric effect in Ni Fe Mn Ga alloy
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DOI：
10.1016/j.jmmm.2006.06.017
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发表时间：
2007-02
影响因子：
2.7
通讯作者：
J. Duan;Peng-nian Huang;Hu Zhang;Y. Long;Guangheng Wu;R. Ye;Yongqin Chang;F. Wan
中科院分区：
文献类型：
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作者：
J. Duan;Peng-nian Huang;Hu Zhang;Y. Long;Guangheng Wu;R. Ye;Yongqin Chang;F. Wan
研究了Ni54.5FeMn20Ga24.5合金的相变过程和磁熵变ΔS。用Fe代替Ni提高了居里温度并降低了马氏体相变温度。从铁磁马氏体到铁磁奥氏体状态的转变导致磁化强度在0.5T以下突然增加，在0.5T以上磁化强度突然减少。随着施加的磁场从 0.5T 增加到 2T，ΔS 的符号从正变为负。对于0至0.5T的外加磁场，正磁熵变ΔS的最大值约为3.1J/kgK。施加磁场从 1.5T 开始增加会导致 ΔS 为负值。对于 2T 的场变化，负 ΔS 的峰值为 -2.1J/kgK。
The phase transition process and magnetic entropy change ΔS of Ni54.5FeMn20Ga24.5alloy were studied. Substitution of Fe for Ni increases the Curie temperature and decreases the temperature of martensitic phase transition. The transition from ferromagnetic martensitic to ferrormagnetic austenitic state leads to an abrupt increase of magnetization below 0.5T and an abrupt decrease of magnetization above 0.5T. The sign of ΔS changes from positive to negative with increasing the applied field from 0.5 to 2T. The maximal value of the positive magnetic entropy change ΔS is about 3.1J/kgK for the applied field from 0 to 0.5T. The increase of applied field from 1.5T results in a negative ΔS. The peak of negative ΔS is -2.1J/kgK for a field change of 2T.