Enhanced magnetostrictive properties of lightly Pr-doped Fe83Ga17 alloys

Abstract

Fe83Ga17Prx alloys, where x = 0, 0.2, 0.4, 0.6 and 1.0, were prepared by a non-consumable vacuum arc melting technique under an inert argon gas atmosphere. The crystal structure and surface morphologies of the alloys were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. Local compositional variations were measured by energy dispersive X-ray spectroscopy (EDXS). The magnetostriction coefficients of the alloys were measured by means of a differential resistive strain sensor. The magnetism of the sample was measured by a vibrating sample magnetometer (VSM). The results show that the parent Fe83Ga17 alloy consists of a single A2 phase of bcc symmetry, whereas the Pr doped Fe83Ga17 alloys are composed of the A2 phase of bcc structure and a small volume fraction of PrGa2 as a secondary phase. Most importantly, with increasing x, the magnetostriction coefficient of the Fe83Ga17Prx alloys first increases reaching a maximum saturation magnetostriction coefficient of 192 ppm for x = 0.6 at a magnetic field strength of 486 kA/m, then decreased. This maximum represents a 400% increase over the parent alloy with a mere 0.6 at% Pr doping.