Magnetoimpedance effect in nanocrystalline Fe90−xBxZr7Cu1Al2 (x=2,4,6,8) alloys

Abstract

The magnetoimpedance of Fe90−xBxZr7Cu1Al2 (x=2,4,6,8) alloys has been measured to investigate the influence of the structural changes in the crystallization process as well as the changes of magnetic properties such as permeability, coercivity, magnetic anisotropy, etc. after thermal treatment. The frequency of magnetoimpedance measurement ranged from 100 kHz to 10 MHz, and the current was fixed at 10 mA for all measurements. Annealing was performed at temperatures of 350, 450, and 550 °C for 1 h in a vacuum. Ultrasoft magnetic behavior has been observed in the samples annealed at 450 °C. The magnetoimpedance ratio coincides with the softness of magnetic properties of thermally treated samples. A giant change of the longitudinal permeability as a function of external field is also observed.