Exploring microstructural origin of squareness-coercivity trade-off in iron-rich Sm-Co-Fe-Cu-Zr magnets

Abstract

A squareness-coercivity trade-off was identified in iron-rich magnets, and the microstructural origin remains unclear. Here, a comparative investigation between two typical magnets was performed from grain boundaries to grain interiors. It clearly revealed that the probability distribution of Cu concentration and the constituent phases among different cell boundaries are largely responsible for the uniformity and the strength of domain-wall-pinning, and thus determines the squareness-coercivity trade-off. On this basis, a strategy for the collaborative optimization of squareness-coercivity in Sm-Co-Fe-Cu-Zr magnets was provided. The above findings deepen our understanding of the correlation between squareness and coercivity and may provide important considerations for the preparation of iron-rich Sm-Co-Fe-Cu-Zr magnets.