摘要
在Heusler合金Ni Mn Ga和NaZn1 3型化合物La(Fe,Co,M)1 3,M =Si,Al中很宽温度区间发现巨大磁熵变△S。这两种材料在室温区的磁熵变△S均显著地超过单质稀土Gd并达到著名的磁热效应材料Gd5Si2 Ge2 合金的磁熵变幅度.Heusler合金Ni Mn Ga中的巨大磁熵变来源于具有一级相变特征的马氏结构相变。NaZn1 3型化合物La(Fe,Co,M)1 3,M =Si,Al中异常巨大的磁熵变与合金中的强的磁晶耦合相关,表现为居里温度附近晶格的巨大负膨胀。材料的低价格和其巨大磁熵变表明,Heusler合金Ni Mn Ga和NaZn1 3型化合物La(Fe,Co,M)1 3,M =Si,Al在很宽的高温区,尤其在室温区作为磁制冷工质非常有吸引力。
Very large magnetic entropy change △S in a wide temperature range was discovered in Heusler alloys Ni-Mn-Ga and NaZn 13-type compounds La(Fe,Co,M) 13, M=Si, Al. In room temperature range, the achieved △S in both materials significantly exceeds that of Gd and reaches that of Gd 5Si 2Ge 2, which is well known for its giant magnetocaloric effect. The great △S in Heusler alloys Ni-Mn-Ga originates from the first-order martensitic-austensitic structural transition and the giant △S in La(Fe,Co,M) 13, M=Si, Al is associated with a strong structural and magnetic interplay, characterized by a drastic lattice contraction at Curie temperature T C. The superiority of low cost and giant magnetic entropy change suggests that both Heusler alloys Ni-Mn-Ga and NaZn 13-type compounds La(Fe,Co,M) 13, M=Si, Al are promising candidates for magnetic refrigerants in an extended high temperature range, especially at room temperature.
出处
《中国科学院研究生院学报》
CAS
CSCD
2002年第2期192-197,共6页
Journal of the Graduate School of the Chinese Academy of Sciences
基金
supportedbytheStateKeyProjectofFundamentalResearch
theNationalNaturalScienceFoundationofChinaandtheBeijingNaturalScienceFoundationofChina.
