Analysis on the inhomogeneous magnetization reversal in the sintered Sm-Co magnet

Abstract

Domain-wall-pinning is one of the ways to realize magnetic hardening for permanent magnet materials. The sintered 2:17 Sm-Co magnets, a most typical pinning-controlled magnet, have complex nano-scaled cellular structures including cellular matrix phase, cell wall phase, and lamellar Zr-rich phase. In this paper, a multiple domain-wall-pinning with cell wall phase dominating and Zr-rich phase participating was proposed through micromagnetic simulation. The simulation results were supported by magnetic domain observation and macroscopic magnetic measurement analysis, which provided a key reference for the correlation between the magnetic properties and microstructure of this kind of magnet. Furthermore, the squareness of the demagnetization curve for the magnet was affected by multiple pinning, including multiple pinning phases and the internal inhomogeneity inside a pinning phase. Our finding can enrich the magnetic hardening mechanism and provide theoretical guidance for the optimization of magnetic properties of the pinning-controlled permanent magnets.