铟替代部分锗对锰钴锗合金磁结构相变及磁热效应的影响

Influence of In-substitution for Partial Ge on Magneto-Structural Transition and Magnetocaloric Effect of MnCoGe Alloy

为研究铟替代部分锗对锰钴锗合金磁结构相变与磁热效应的影响,采用电弧熔炼方法制备了Mn_1Co_1Ge_1和Mn_1Co_1Ge_(0.99)In_(0.01)合金,研究了这两种合金的物相、相变和磁热效应,以及升、降温测试方式得到的Mn_1Co_1Ge_(0.99)In_(0.01)合金的磁化曲线。结果表明:铟替代部分锗后,合金中并未产生杂相,其相变特性由二级磁相变变为一级磁结构相变;Mn_1Co_1Ge_(0.99)In_(0.01)合金在不同的相变方向上具有不同的磁滞后行为;升温测试时,Mn_1Co_1Ge_(0.99)In_(0.01)合金在5,7T磁场强度下的磁熵变峰值分别为52.2,64.1J·kg^(-1)·K^(-1),降温测试时的磁熵变峰值分别为40.8,50.9J·kg^(-1)·K^(-1);升温测试时,Mn_1Co_1Ge_(0.99)In_(0.01)合金在7T磁场强度下的制冷能力为477J·kg^(-1),降温测试时为264.4J·kg^(-1)。

In order to investigate the effects of In-substitution for partiM Ge on magneto structural transition and rnagnetocaloric effect （MCE）,Mn_1Co_1Ge_1 and Mn_1Co_1Ge_（0.99）In_（0.01） alloys were prepared by arc-melting method, and phase composition, phase transition, MCE and magnetization isotherms of Mn_1Co_1Ge_（0.99）In_（0.01） alloy obtained by warming and cooling modes were studied. The results show that In-substitution for partial Ge would not lead to impurity phase, but could turn the second order magnetic transition to first-order nlagneto-structural transition. Mn_1Co_1Ge_（0.99）In_（0.01） alloy owned different magnetism hysteresis behaviors on different phase transformation directions. In warning mode, the maximal magnetization entropy ofMn_1Co_1Ge_（0.99）In_（0.01）, alloy at magnetic intensigy of 5, 7 T were 52.2,64.1J·kg-（-1）·K-（-1）, respectively; in cooling mode, those were 40.8,50.9J·kg-（-1）·K-（-1）,respectively. The refrigeration capacity of Mn_1Co_1Ge_（0.99）In_（0.01） alloy at magnetic intensity of 7 T was 477J·kg-（-1）, and that was 264.4J·kg-（-1）.