The effect of changes in the local atomic structure on the magnetic properties of amorphous iron-based alloys deformed by high-pressure torsion at different temperatures

摘要

The changes of local atomic structure of amorphous magnetically soft iron-based Fe50Ni33B17, Fe54Ni29B17, Fe58Ni25B17, and Fe75Si8B17 alloys have been studied upon high-pressure torsion (HPT) at 77 K and 293 K. The set of structure research methods used for the study included EXAFS spectroscopy in synchrotron radiation, X-ray diffraction, transmission electron microscopy, and differential scanning calorimetry. The effect of HPT regimes on the character of the local atomic environment of iron and nickel atoms has been established. The magnetic properties of the alloys were measured with a vibration magnetometer at room temperature. The correlation between the specific saturation magnetization and the parameters of the local atomic structure has been revealed. It is shown that the amorphous state after HPT is characterized by a significant change in the saturation magnetization and coercive force relative to those of the initial state. (C) 2019 Elsevier B.V. All rights reserved.