Hyperfine structure variations in an Fe-Cr-Co alloy exposed to electron irradiation: Mössbauer spectroscopy characterization

Fe-Cr-Co alloys are promising permanent magnetic materials for many applications. Although the magnetic properties of these alloys have been intensively studied, the hyperfine structures that govern the overall magnetic performances still need to be clearly demonstrated. In this study, to elucidate the mechanisms of the magnetic stability during exposure to electron irradiation, Mössbauer spectroscopy was utilized to characterize the hyperfine structure of an Fe-Cr-Co alloy before and after electron irradiation. It was determined that, after being exposed to electron irradiation, the defects and the atom displacements varied significantly and thus resulted in remarkable differences in the hyperfine magnetic fields and the electron distributions around the atoms. As a result, the ratio of the ferromagnetic α1 phase and the paramagnetic α2 phase varied accordingly, and the variation of the ferromagnetic environment around the magnetic atoms accounted for the reduction in the hyperfine magnetic field. These results provided a pathway to determining the effects of electron irradiation on the electron hyperfine structure in Fe-Cr-Co alloys and shed light on the damage mechanisms of Fe-Cr-Co alloys from exposure to electron irradiation.