Crystal structure and magnetic properties of SmCo7-xHfx compounds

The crystal structure and magnetic properties of SmCo7-xHfx (x=0.05,0.1,0.2,0.3) compounds were studied by means of x-ray powder diffraction and magnetic measurements. The as-cast compounds SmCo7-xHfx with x=0.1 and 0.2 crystallize in the TbCu7-type structure with the space group P6/mmm. According to the structure refinement, the doping element Hf prefers to occupy the 2e site. The compounds have high Curie temperatures (1080 K for x=0.1, 1075 K for x=0.2), large saturation magnetization (104 emu/g for x=0.1, 102 emu/g for x=0.2 at 5 K), and large magnetic anisotropy fields (244 kOe for x=0.1, 282 kOe for x=0.2 at 5 K) with strong uniaxial magnetocrystalline anisotropy. (C) 2004 American Institute of Physics.