Microstructure modification induced giant coercivity enhancement in Sm(CoFeCuZr)z permanent magnets

Microstructure modification induced giant coercivity enhancement from 950 to 1688 kA/m has been achieved in Sm(Co_0.665Fe_0.25Cu_0.06Zr_0.025)₇ permanent magnets via Cu powders doping. Microstructure observation shows that in original magnet there are Cu-lean regions along the grain boundary area, where regular cellular structure does not form. After Cu powders doping, most Cu-lean regions disappear. Comparison of magnetic domain reversal between the original magnet and doped magnet indicates that reversed domain propagation was substantially restrained due to the elimination of the Cu-lean region. Moreover, the pinning field increases by 83.3% after Cu doping, having good agreement with coercivity enhancement.