Temperature dependence of coercivity for Co-Sm permanent magnet alloys

The demagnetization properties of a series of sintered Co-Sm magnets have been measured over the range 0 to 750 K. The intrinsic coercive force of the samples varied from 19 to 65 kOe at 27 K, but decreased with increasing temperature to zero at about 700 K. The change of relative coercivity, H
ci
(T)/H
ci
(77 K), with temperature was the same for all the samples. Thus, it appears that the factors which influence the magnitude of coercivity do not influence the temperature dependence.