With the intention to explore excellent magnetocaloric materials, the intermetallic compound GdPd was synthesized by arc melting and heat treatment. The microstructure, magnetic and magnetocaloric properties of the intermetallic compound of GdPd were investigated by X-ray diffraction(XRD), scanning electron microscopy(SEM) and the physical property measurement system(PPMS). A large reversible magnetocaloric effect is observed in GdPd accompanied by a second order magnetic phase transition from paramagnetism to ferromagnetism at ～39 K. The paramagnetic Curie temperature(θp) and the effective magnetic moment(μ_(eff))are determined to be 34.7 K and 8.12 μ_B/Gd,respectively. The maximum entropy change(|△S_M^(Max)|) and the relative cooling power(RCP) under a field change of 5 T are estimated to be 20.14 J/(kg·K) and 433 J/kg, respectively. The giant reversible magnetocaloric effects(both the large△S_M and the high RCP) together with the absence of thermal and field hysteresis make the GdPd compound an attractive candidate for low-temperature magnetic refrigeration.
采用直流磁控溅射法制备Dyx(Fe47.5Pd52.5)100-x(x=0,2.2,3.2,4.4,5.6)薄膜,X射线衍射实验结果表明:添加稀土元素Dy可以大幅缩短从无序的fcc相转变为有序的fct相的退火时间和退火温度,增加相转变的驱动力;此外适当添加Dy元素还具有细化晶粒的作用,晶粒尺寸可达到12~31 nm,适当的晶粒尺寸有利于晶粒之间的交换耦合作用。薄膜的磁滞回线表明:矫顽力Hc与剩磁比Mr/Ms随Dy含量的增加而先急剧增加后减小,当稀土含量x=3.2时,矫顽力的最大值为3.27 k Oe。随着退火温度的增加,矫顽力的变化也是先增加后下降,并且在Ta=550℃时达到最大。
