Temperature dependence of coercivity and magnetization reversal mechanism in Sm(Co{sub}(bal)Fe{sub}0.1Cu{sub}yZr{sub}0.04){sub}7.0 magnets

摘要

The temperature dependence of coercivity in Sm(Co{sub}(bal)Fe{sub}0.1Cu{sub}yZr{sub}0.04){sub}7.0 magnets with y = 0 to 0.20 has been systematically studied. Two models are discussed with respect to the temperature dependence of coercivity. One model considers only domain wall (DW) pinning and explains the "abnormal" behavior as a temperature-induced transition from a repulsive DW pinning to an attractive one. The other model assumes a combination of pinning and nucleation of DWs in magnetically isolated 2: 17 cells. In this model, the cell-boundary pinning of DWs takes place in the alloys with low Cu content at temperatures below the Curie temperature of 1 : 5 phase. Nucleation controls the magnetization reversal in the case of complete magnetic isolation of the 2: 17 cells. This condition is expected to be fulfilled at any temperature above RT in the Cu-rich magnets, and only above Curie temperature of the 1 : 5 phase in the alloys with lower Cu content.