Influence of the initial temperature on the thermal remagnetization of SmCo 5 sintered magnets

Abstract

Modern permanent magnets show an irreversible increase of the remanent magnetization for increasing temperature. This thermal remagnetization (TR) occurs after DC-demagnetization at the initial temperature T 0 followed by heating. The TR is especially large for well-aligned sintered SmCo 5 permanent magnets and is strongly correlated with the grain-interaction and the temperature coefficient of the coercivity. We present a systematical study on the influence of the initial temperature T 0 on the TR of SmCo 5 sintered magnets experimentally and theoretically. We find that the TR-maximum increases with decreasing T 0, whereas its position T max shits slightly to lower temperatures with decreasing T 0. This together with the dependence on the sample demagnetization factor N, is in agreement with the results of our model calculation.