Heat-treatment of off-stoichiometric SmCo5magnets

Demagnetization loop shapes for off-stoichiometric SmCo5magnets subjected to heat-treatment between 700°C and 900°C suggest that both domain wall nucleation and trapping mechanisms are operative. Results are interpreted under the assumption that the nucleation sites are peripheral Sm2Co17and that the principal trapping sites are Co vacancies generated in hyperstoichiometric, i.e. greater than 33.8 wt% Sm, SmCo5.