Influence of isotropic short-range compositional ordering on the properties of magnetic hysteresis of amorphous cobalt-based alloy with near zero magnetostriction

Abstract

The regularities of the effect of various types of heat treatment on the magnetic hysteresis properties (MHP) of the amorphous alloy Co69Fe3.7Cr3.8Si12.5B11, which is in the initial (after quenching of the melt) or pre-annealed condition, are studied. At the annealing temperature Ta below the Curie point TC (260°C), the key role in the formation of MHP is played by the stabilization of the domain borders (DB) owing to the development of the process of directed ordering. High-temperature pre-annealing at Ta < TC followed by quenching in water does not prevent the degradation of MHP as a result of the DB stabilization (thermally reversible effect). After the annealing at Ta < TC, there is a degradation of MHP owing to the development of the process of clustering registered by low-angle X-ray scattering. Being an irreversible process, this type of clustering must not affect the dependence of MHP on the annealing temperature when the samples are exposed to a high-temperature pretreatment. However, the experiments have shown that, on the curve of the dependence of MHP on the temperature of the repeated isochronous annealing at Ta < TC, the degradation of MHP is clearly observed, as in the initial samples. This degradation occurs because of clustering caused by an isotropic compositional short-range order, which is a reversible process. Thus, it is proved that the isotropic compositional short-range order can affect the level of MHP of amorphous alloys.