RCo_(12-x)Ti_x(R=Y,Sm)化合物的结构与磁性研究

Structural and magnetic properties of R Co_ (12-x) Ti_x ( R =Y and Sm) compounds

通过x射线衍射分析和磁性测量研究了RCo1 2 -xTix(R =Y ,Sm)化合物的结构与磁性 ,所有化合物全部具有ThMn1 2 型结构 .常规取向样品的x射线衍射谱表明 ,SmCo1 2 -xTix 化合物具有室温面磁晶各向异性 ,而YCo1 2 -xTix 化合物具有室温单轴磁晶各向异性 .随着Ti含量的增加 ,SmCo1 2 -xTix 和YCo1 2 -xTix 化合物的居里温度TC 及饱和磁化强度Ms 均单调降低 .YCo1 2 -xTix 化合物的磁晶各向异性场 μ0 Ha 随Ti含量的增加而降低 ,而SmCo1 2 -xTix 化合物的磁晶各向异性场 μ0 Ha 在x =1.74时出现一极大值 ,这可以用双次晶格模型来解释 .

Magnetic and structural properties of RCo12-xTix with R=Y and Sm compounds have been investigated by using x-ray diffraction and magnetic measurements. It was found that all compounds investigated are almost of a single phase with the ThMn12-type structure. x-ray diffraction, patterns of magnetically aligned powder samples indicate that the easy magnetization directions (EMD) at room temperature are in the basal plane for SmCo12-xTix compounds while for YCo12-xTix. compounds the EMDs are along the c-axis. The lattice parameters increase monotonically with increasing Ti content for all the compounds investigated. The Curie temperature T-c decreases monotonically with increasing Ti content for both YCo12-xTix and SmCo12-xTix The saturation magnetization M-s decreases with increasing Ti content for all the systems. The anisotropy field mu(0)H(a) of YCo12-xTix compounds decreases monotonically with increasing Ti content, while the Ti content dependence of the anisotropy fields mu(0) H-a for SmCo12-xTix compounds exhibits a maximum at about x=1.74, which can be understood in terms of a two-sublattice model of anisotropy.