Mechanism of the anomalous temperature dependence of coercivity in Sm(Co,Fe,Cu,Zr)z high-temperature magnets -: art. no. 042504

Coercivity mechanism of the precipitation-hardened Sm(Co,Fe,Cu,Zr)(z) high-temperature magnets was found to vary with temperature by measurements of reversible magnetization. The magnetization reversal is mainly controlled by domain-wall pinning when temperature is lower than 800 K, while is mainly dominated by nucleation at higher temperature. It is interesting to find that the anomalous temperature dependence of coercivity H-c(T) near Curie temperature of the 1:5 phase is caused by the fast drop of intergranular exchange coupling. This mechanism can also explain the coercivity behavior that the anomalous H-c(T) tends to disappear with increasing z value.