Mossbauer Spectroscopy Study of Fe75.3Ni0.8Cr0.9Si8.7B14.3 Ferromagnetic Alloy after Thermal Annealing, Laser and Electron Beam Irradiation

Abstract

This paper presents a Mӧssbauer spectroscopy study of the behavior of Fe_75.3Ni_0.8Cr_0.9Si_8.7B_14.3 ferromagnetic alloy after thermal annealing, cw laser and high-energy electron beam irradiation.  Thermal annealing at 450 ^oC caused structural relaxation of the alloy system, supported by an increase in the average magnetic hyperfine field and width of the field distribution, accompanied by a significant out-of-plane reorientation of the magnetic moment directions.  Thermal annealing at temperatures of 550-750 ^oC determined crystallization of the bulk of the specimens and alpha-(FeNiCr), (FeNiCr)₃(BSi) and (FeNiCr)₂(BSi) crystalline phases were identified. At the highest treatment temperature, (FeNiCr)₃(BSi) partially decomposed into alpha-(FeNiCr) and (FeNiCr)₂(BSi).  Cw laser irradiation essentially preserved the preferred in-plane orientation of the magnetic moment directions, with a slight tendency of an out-of-plane reorientation.  Irradiation of the Fe_75.3Ni_0.8Cr_0.9Si_8.7B_14.3 alloy system with 11 GeV electrons maintained the in-plane direction of bulk magnetization in the beam dump sample and caused an even more pronounced in-plane direction of the magnetic moments in the target platform sample.  This is due to the low value of the magnetostriction constant of the Fe_75.3Ni_0.8Cr_0.9Si_8.7B_14.3 system.  Both laser and electron beam irradiation were demonstrated to keep the amorphous phase of the Fe_75.3Ni_0.8Cr_0.9Si_8.7B_14.3 alloy, making it a strong candidate for radiation-resistant materials.