Ordering, magnetostriction, and elastic properties in Fe-27.5at.% Ga alloy single crystals

Abstract

Fe–Ga alloys, with composition around 27.5at.% Ga, can be heat treated to obtain α (A2, bcc), α″ (D03-like, ordered bcc), β-Fe3Ga (D019, ordered hexagonal), and α-Fe3Ga (L12 ordered fcc) phases. In this work, the influence of α″ ordering on the magnetostriction coefficient (3∕2) λ100, elastic constants (C11, C12, and C44), and the magnetomechanical coefficients (B1) of the single crystals of α-Fe-27.5at.% Ga and α″-Fe-27.5at.% Ga alloy is examined. Single crystals of Fe-27.5at.% Ga were grown using the vertical Bridgman technique. Magnetostriction measurements were performed using [100]-oriented single crystals. Elastic constants were estimated using resonant ultrasound spectroscopy and analysis technique. It is shown that the α″ ordering in Fe-27.5at.% Ga alloy decreases the (3∕2) λ100 value from that of α phase. This is consistent with our previous work on polycrystalline Fe-27.5at.% Ga alloys. The α-Fe-27.5at.% Ga alloy single crystal was found to have a higher magnetoelastic coupling constant than the α″-Fe-27.5at.% Ga alloy single crystal.