COERCIVITY ANALYSIS IN SM(CO,CU,FE,ZR)7-8 MAGNETS

The coercivity mechanisms in Sm(Co, Cu, Fe, Zr)7-8 magnets are analysed. The experimental results are discussed with reference to those obtained in sintered magnets. From the high temperature part of the thermal dependence of the coercive field, consistent values of the phenomenological parameters alpha (barrier coefficient) and N(eff) (effective dipolar coefficient) are obtained. However, the effects of activation at low temperatures are much more important than in sintered magnets and the angular dependence of H(c) does not correspond to that usually expected for pinning-controlled coercivity.