Dynamic circular hysteresis in Co-based amorphous microwires

Abstract The circular hysteresis loops in CoFeSiB negative magnetostrictive amorphous wires with glass cover have been measured at frequencies up to 250 kHz under the effect of axial DC magnetic field. The loops are partitioned into reversible and irreversible portions assigning them corresponding permeability parameters. It is demonstrated that the introduced permeabilities are characterised by different field-frequency behaviour. This analysis is helpful to understand the variety of magnetoimpedance characteristics reported for different frequency ranges and excitation conditions.