Crystal structure and magnetic properties of SmFe9-xCox alloys

The crystal structure and magnetic properties of SmFeg_xCox （x = 0, 1, 3, 5） alloys were studied by X-ray powder diffraction （XRD） and magnetic measurements. The Th2Znl7-type structure of the as-cast state is changed to TbCu7-type structure after quenching to a rotating molybdenum roll under certain velocity （12, 20, and 32 m.s-l）. The （002） XRD peak appears and ~-Fe phase disappears when the Co is added up to x = 5. Saturation magnetization of SmFe9 under different temperature shows 9 % change （112-102 A.m2.g-1） when the temperature is higher than 200 K. The saturation magnetization is 115 A.m2.g-1 and coercivity is 0.304 T at 5 K for SmFe9 alloys. Increased saturation magnetization and decreased coercivity can be obtained for Co added up to x = 5 at 5 K.