Anomalous loss factor of annealed nearly non-magnetostrictive amorphous wire

Abstract The low-field complex AC permeability, μ=μ′−jμ″, of a nearly non-magnetostrictive amorphous wire has been measured after 470°C annealing as a function of frequency f (=0.1 –102 kHz) and DC bias field HDC(=0–7.2 A/m). With increasing HDC, the low-f eddy-current anomaly factor η increases from 2.8 to 11.3, and after a low-f rise, the loss factor tan δ(=μ″/μ′) versus f curve changes from one showing a maximum 1.28 and a minimum 1.01 at 4.5 and 22 kHz, respectively, with a final value of 1.49 at 102 kHz to one with a slow increase from 0.34 at 7 kHz to 0.44 at 102 kHz. These anomalous behaviors are explained by a helical magnetization core-shell model.