ANISOTROPIC DEPENDENCE OF GIANT MAGNETO-IMPEDANCE OF AN AMORPHOUS FERROMAGNETIC RIBBON ON BIASING FIELD

摘要

The magneto-impedance (MI) in an amorphous ribbon of nominal composition Fe73.5Nb3Cu1Si13.5 B9 has been measured at 1 MHz at room temperature for different configurations of exciting AC and biasing DC fields. A large drop in both resistance and reactance is observed as a function of the magnetic field. When the DC and AC fields are parallel but normal to the axis of the ribbon, a smaller magnetic field is needed to reduce the impedance to its small saturated value compared to the situation when the fields are along the axis of the ribbon. A larger DC field is required to lower the impedance when the DC field acts perpendicularly to the plane of the ribbon. Such anisotropy in magneto-impedance is related to the anisotropic response of the magnetization of the ribbon. The large change of impedance is attributed to a large variation of AC permeability on the direction and magnitude of the DC biasing field.