【摘要】 用非自耗电弧炉熔炼了Gd5+xSi2Ge2系列样品。用X射线粉末衍射(XRD)和Rietveld方法研究了Gd5+xSi2Ge2系列样品的晶体结构。用自制的仪器测量了样品的居里温度,用振动样品磁强计研究了样品的磁卡效应。对样品的晶体结构分析结果表明:Gd的含量x的变化对Gd5Si2Ge2化合物的晶体结构有较大的影响,当x>0时,样品中含有Gd5(Si,Ge)4和Gd5(Si,Ge)3两个相,并且随着x的增加Gd5(Si,Ge)4相会减少,Gd5(Si,Ge)3相会增加;当x<0时,样品会形成Gd5(Si,Ge)4和Gd(Si,Ge)两相,并且随着x的减少Gd5(Si,Ge)4相会减少,Gd(Si,Ge)相会增多。对样品的磁性能分析结果表明:Gd的含量x>0和x<0时都会降低样品的磁卡效应,样品的居里温度会随着x的增加而增加。更多还原

【Abstract】 Alloys of Gd_5+XGe₂Si₂ （x=0.5, 0.25, 0, -0.25, -0.5） were prepared by arc melting under argon atmosphere. The crystal structure for all samples was measured using X-ray diffraction, The magnetic measurements have been used to study the effect of increasing the properties of Gd on the Curie temperature and the magnetic entropy change of Gd₅Ge₂Si₂. The experimental results show that there are two phases of Gd₅（Si,Ge）₄ and Gd₅（Si,Ge）₃ ,where x>0 ,and two phases of Gd₅（Si,Ge）₄ and Gd（Si,Ge） ,where x<0. The Curie temperature of samples could be increased when the properties of Gd is increased, the magnetocaloric effect of the Gd_5+xGe₂Si₂, where x=0, is 4.31 J/kg·K,the largest in all of samples ,at their Curie temperatures.更多还原