Crystal structure and magnetic properties of melt spun Sm(Co, V)7 ribbons

The crystal structure and magnetic properties of melt spun Sm(Co, V) 7 ribbons have been investigated. It was found that SmCo7-xVx ribbons may crystallize in pure TbCu7-type structure for x=0.1-0.3 spun at a high wheel speed of 40 m/s. The structure refinement results show that the doping element V prefers to occupy the 2e site of TbCu7-type structure. Besides, transmission electron microscopy images show that with increasing V content, the grain size was refined from 200-400 nm for x=0.1 to 40-100 nm for x=0.3. As a result, the intrinsic coercivity enhances effectively from 1.9 kOe for SmCo7 ribbon to 11.5 kOe for SmCo6.7V0.3 ribbon. It is also verified that a slight addition of C to SmCo7-xVx could further refine the microstructure, resulting in the improvement of the magnetic properties of SmCo7-xVx ribbons. The optimal magnetic properties of sigma(r)=58.7 emu/g, H-i(c)= 13.5 kOe, and (BH)(max)=9.3 MG Oe can be obtained for SmCo6.9V0.1C0.1 ribbon. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3061907]