Magnetic softness and magnetization dynamics of FeSiBNbCu(P,Mo) nanocrystalline alloys with good high-frequency characterization

摘要

In this study, the microalloying effects of P and Mo on thermal behavior, magnetic softness and magnetization process of FeSiBNbCu(P,Mo) nanocrystalline alloys were investigated systematically. The P and Mo bearing alloys exhibit pronouncedly improved magnetic softness, including extremely low coercivity of about 0.7 A/m, high saturation magnetic flux density of about 1.40 T, high permeability over 3.0 x 10(4) at 1 kHz. The excellent magnetic softness could be attributed to uniform dual-phase microstructure and wide strip magnetic domains after optimum annealing. The P and Mo containing alloys also have good high-frequency characterization, especially, the permeability at 100 kHz is still over 1.53 x 10(4). These alloys also have relatively low pinning field of 20-30 A/m, which means lesser defects and easier magnetization. Through observing the changes of magnetic domains and mu with applied field increasing, we found that the increase of mu is corresponding to reversible and irreversible movement of domain walls, after reaching the maximum, the decrease of mu is related to the rotation of magnetic moment and the split of domains.