Micromagnetics of Nd–Fe–B magnets at finite temperature

Abstract

Abstract A three-dimensional micromagnetic model for Nd–Fe–B magnets, where the polycrystalline grain size and grain boundary width are adjustable, is built to calculate the finite temperature magnetic properties by the Hybrid Monte Carlo method. At 300 K, it is found that the increase of the energy product (BH)max of Nd–Fe–B is mainly contributed by the higher saturation magnetization M s. M–H loops are simulated from 300 to 450 K, and the measured temperature-dependent coercivity H c(T) and remanence M r(T) are explained quantitatively and fit well with experiments.