High temperature magnetic properties of Fe-Cu-Nb-Si-B cores with creep-induced anisotropy

Fe-Cu-Nb-Si-B ribbons with creep-induced anisotropy fabricated by continuous stress-annealing were formed into toroidal cores. The temperature dependence of their magnetic loss and relative permeability at [B.sub.m] = 0.1 T was evaluated in the frequency range of 0.5-1 MHz and temperature range from room temperature to 523 K. We found that the cores can be used up to 523 K without magnetic property deterioration. This suggests that the proposed cores have superior high temperature properties compared with conventional gapped-ferrite cores allowing use at high temperature. Index Terms--Continuous stress-annealing, creep-induced anisotropy, high temperature properties, low permeability, magnetic core, nanocrystalline.