Perminvar Effect in Amorphous Hitperm Alloy

Influence of the directional ordering on magnetization processes in the amorphous $Fe_{44.5}Co_{44.5}Zr_7B_4$ alloy was investigated in the temperature region of 27 to 300°C for stabilization times of up to 1000 min by means of the Perminvar effect. The time-temperature dependent Perminvar effect was found to be very sensitive on the stage of the domain structure stabilization. The Perminvar critical fields $H_{CR}$ were shifted to higher values with increasing stabilization temperatures and times. At lower temperatures, the susceptibility increases over wide range of the measuring fields. Stabilization at higher temperatures causes that the susceptibility abruptly increases in the narrow field range. The record critical field $H_{CR} =246 Am^{-1}$ was obtained.