Ni46Mn35Ga19单晶大的磁熵变和磁控形状记忆效应

Large Magnetic Entropy Change and Magnetic-Controlled Shape Memory Effect in Single Crystal Ni46Mn35Ga19

摘要:

采用多种测量手段，对制备出的转变温度在室温以上的Ni46Mn35Ga19 单晶的物性进行表征。电阻和交流磁化率结果表明，该材料的磁转变和马氏体相变是同时发生的。定温磁化强度测量得出材料磁熵变的增长速率高达9.0 J/kg·K·T，在1274 kA/m（1.6 T）的磁场下，磁熵变达13.8 J/kg·K。此外，应变测量表明，伴随该磁熵变，材料展现出应变量分别高达–0.89%和–1.90%的自发和磁控双向形状记忆效应

Abstract:

Physical properties of Ni46Mn35Ga19 single crystal with transition temperatures above room temperature were investigated by various measuring methods. The measuring results of the resistance and ac susceptibility indicate that the magnetic transition and martensitic transformation can occur simultaneously in this alloy. The measurements of the isothermal magnetization show that the increasing rate of magnetic entropy change in this alloy is 9.0 J / kg·K·T. A large magnetic entropy change of 13.8 J/kg·K is obtained under the field of 1.6 T in the single crystal. Furthermore, the strain measurement shows that accompanying with magnetic entropy change, the alloy exhibits a large spontaneous transition strain of –0.89% and a large magnetic-field-enhanced strain of –1.90%.