NdNi2Ge2化合物的结构和电磁输运性质

摘要

The sample of compound NdNi2Ge2 is prepared by arc melting.The crystal structure is analyzed using powder X-ray diffraction and refined with Rietveld is method.It is shown that NdNi2Ge2 intermetallic compound crystallizes into a tetragonal structure with space group of I/4mmm and its lattice constant is a=4.120（1）,c=9.835（0）,Z=2.Nd atoms occupy 2a positions,Ni atoms 4d positions and Ge atom 4e positions.NdNi2Ge2 intermetallic compound has a Curie-Weiss constant of 25.8 and Curie-Weiss temperature of 6.24 K.The effective magnetic moment is 3.69μB,which is very close to that of Nd3＋.It implies that the magnetic moment originates mainly from Nd3＋ ion.The resistivity varies from 0.3 Ω·μm—1.1 Ω·μm.Fitting results show that this intermetallic compound is semimetal.%利用非自耗真空电弧熔炼法制备了NdNi2Ge2化合物样品,采用X射线粉末衍射技术和Rietveld全谱拟合分析方法测定了其晶体结构.结果显示该化合物的空间群为I4/mmm,点阵参数为：a=4.120（1）,c=9.835（0）,Z=2,Nd原子占据2a晶位,Ni原子占据4d晶位,Ge原子占据4e晶位.NdNi2Ge2化合物呈现顺磁性,应用居里-外斯定律拟合计算得到居里-外斯常数为25.8,居里-外斯温度为6.24K.有效势磁矩为3.69μB,这与理论计算Nd3＋的磁矩相符,表明磁矩主要源于Nd3＋.电阻率变化范围为0.3Ω·μm-1—1Ω·μm,电阻曲线拟合显示NdNi2Ge2呈半金属性.