Grain boundary modification induced magnetization reversal process and giant coercivity enhancement in 2:17 type SmCo magnets

Grain boundary modification induced giant coercivity enhancement from 945 kA/m to 1904 kA/m was achieved in Sm25Co48Fe20Cu5Zr2 magnets by doping 0.4 wt% CuO. Different magnetization reversal behaviors were clearly observed between un-doped and doped magnets. Compared with un-doped magnets, Cu enrichment along grain boundary promoting regular cellular structure was obviously found in doped magnet. The in-situ Kerr observation indicated that complete cellular structure could strengthen the pinning field of grain boundary regions and the propagations of magnetization reversals into interiors of grains were restrained by the modified grain boundaries, which resulted in the remarkable coercivity increment.