2: 17型结构Gd-Fe-Co-Ga化合物的结构与磁性

用电弧熔炼的方法制备了Gd₂（Fe_1-xCo_x）₁₅Ga₂（0≤x≤1.0）和Gd₂（Fe_0.8Co_0.2）_17-yGa_y（0≤y≤8）化合物，通过Ｘ射线衍射和磁性测量手段研究了它们的结构和磁性．实验结果表明它们都是2∶17型结构的单相化合物．Gd₂（Fe_{1 关键词：}

STRUCTURAL AND MAGNETIC PROPERTIES OF Gd Fe Co Ga COMPOUNDS WITH 2∶17 TYPE STRUCTURE

The compounds of Gd₂（Fe_1-xCo_x）₁₅Ga₂(0≤x≤1.0) and Gd₂（Fe_0.8Co_0.2）_17-yGa_y(0≤y≤8) were prepared by arc melting. Their structure and magnetic properties have been studied by means of X ray diffraction and magnetic measurements. Experimental results show that single phase compounds with the 2∶17-type structure were obtained for all samples. It was found that the unit cell volume of Gd₂（Fe_1-xCo_x）₁₅Ga₂ compounds decreases, while the Curie temperature T_c increases monotonously with increasing Co concentration. The saturation magnetization M_s at 1.5K first increases with increasing x, then decreases, showing a value of maximum at x=0.2. For Gd₂（Fe_0.8Co_0.2）_17-yGa_y,the unit cell volume increases, the Curie temperature and the saturation magnetization at 1.5K decrease monotonously with increasing Ga content. The substitution of Co or Ga for Fe in Gd₂Fe₁₇ compounds results in a change of magnetocrystalline anisotropy of Fe or Co sublattice from easy plane to easy c-axis at room temperature. This is likely related to the preferential site occupancy of Ga atom.