低磁场下获得巨磁热效应的GdSiGeZn合金

在研究Gd5Si2-xGe2Znx,Gd5Si2-zGe2-zZn2z系列合金的等温磁熵变和居里温度时发现,Zn的微量变化对合金的磁热性能影响很大.当x或者2z为0.001时,在1.5 T外加磁场变化下,其最大等温磁熵变分别为20.70 J/(kg.K)(x=0.001)和25.30 J/(kg.K)(2z=0.001),居里温度分别为284 K(x=0.001)和280 K(2z=0.001),其磁热性能远高于没有添加Zn元素的合金(5.03 J/(kg.K)).实验证明,微量元素Zn对Gd5Si2Ge2化合物的合金化处理,可使其在低磁场下的磁热效应得到巨幅提高,其最大等温磁熵变优于文献报道的铸锭合金Gd5(Si1-yGey)4及其他添加元素(如Ga,Sn,Cu,B,Al,Bi,Co,Fe,Ni,Mn,C,H等)替代Si或Ge时在5 T高外加磁场变化下的等温磁熵变.

Magnetocaloric Effect of GdSiGeZn Compound under Applied Low Magnetic Field

It was found in a study on the magnetocaloric effect of Gd_5Si_(2-x) Ge_2Zn_x and Gd_5Si_(2-z) Ge_(2-z)Zn_(2x) serial alloys that a trace amount of change of Zn element has a great impact on magnetocaloric properties of GdSiGeZn.The maximum isothermal magnetic entropy change(△S_M)reaches 20.70 J/(kg·K)at 284 K and 25.30 J/(kg·K)at 280 K for x=0.001 and 2z=0.001.These magnetocaloric properties are better than that of undoped GD_5Si_2Ge_2 compound.Experimental results show GD_5Si_2Ge_2 compound which are alloyed by a trace amount of Zn element has better magnetocaloric properties than that of GD_5Si_2Ge_2 compound alloyed by other elements reported in the literature.The over-all magnetocaloric properties are the best among other Gd_5Si_2Ge_2 alloys upon 5 T applied field.