Pulse current training induced marked improvement of soft magnetic properties in Fe-based amorphous alloys

It is difficult to fine-tune the atomic local structure and magnetic domain structure globally to evade the saturation magnetization (<i>B</i>_s)- coercivity (<i>H</i>_c) trade-off in amorphous alloys with high-Fe content. Herein, a unique pulse current training is introduced to optimize the soft magnetic properties of Fe-based amorphous alloys, achieving 1.78 T <i>B</i>_s and 1.6 A/m <i>H</i>_c in Fe_83.3Si₄B₈P₄Cu_0.7. Structural analysis shows that low coercivity is due to the almost no pinning-sites magnetic domain structures despite a relative large grain size of 25 nm. Training accumulates energy to activate soft regions and rearrange structure, eliminating quenching-induced stresses and inhomogeneities to minimize reversal pinning. Pulse current training offers a promising and efficient approach to address the saturation magnetization-coercivity trade-off issue in Fe-based soft magnetic amorphous alloys by accumulating energy to gradually modulate microstructures.