Influence of Dy substitution for Ga on the magnetic properties of arc-melted Fe-Ga alloys

Abstract

The structural, magnetic, and magnetostrictive properties of Fe73-Ga27-x-Dyx (x = 0, 0.25, 0.50, 0.75, and 1) alloys synthesised by arc melting and quenching at 1000 °C were investigated. X-Ray Diffraction (XRD) analysis confirms the Body-Centered Cubic (BCC) nature of the alloys and the presence of an A2 phase of α-Fe throughout the composition, despite the presence of Dysprosium (Dy). It was revealed that the grains are primarily composed of Fe and Ga, but the grain boundaries contain Fe, Ga, and a very high concentration of Dy. The grains indicate that Dy segregates more at grain boundaries. The low saturation magnetization ∼100 emu g−1 achieved at x = 0.25 is due to Dy-rich phase precipitation. The enhanced magnetostriction ∼119 ppm is related to a significant number of Dy-rich phase precipitates and short-range ordering. However, after x = 0.50, the amount of Dy-rich precipitates has a negative impact on the magnetostrictive behaviour of Dy-substituted Fe-Ga alloys, resulting in a decrease in magnetostriction. This demonstrates that the inclusion of Dy enhances the magnetostrictive quality of Fe-Ga alloys.