Investigation on the magnetizing field dependence of coercivity in NdFeB and SmFeN magnets

The dependence of the coercivity on the maximum applied field is found to be mainly dominated by the distribution of the critical fields originating from the grain misalignment. For aligned magnets the coercivity reaches its saturated value at a magnetizing field much smaller than the saturated coercivity due to the small angular deviations from the easy axis of the sample. For isotropic materials the coercivity increases smoothly with increasing magnetizing field due to the isotropic grain alignment, where the magnetizing field required to saturate coercivity should be larger than the coercivity due to the existence of grains with large angles between the direction of the external field and the c-axis of the misaligned grain.