Magneto‐elastic interactions in Fe–Ga alloys

The elastic anisotropy of iron’s most common α‐structure increases significantly when gallium is substituted for a fraction of the iron. Concurrently occurring, the tremendous boost in tetragonal magnetostriction [one order of magnitude above that of pure Fe, 3/2λ100(Fe81Ga19)=400 ppm] makes Fe–Ga alloys important for magnetoelastic applications. Measurements of the elastic tensor of Fe–Ga single crystals, with or without a magnetic field and within 4–300 K, were performed using the resonant ultrasound spectroscopy technique on 100‐cut rectangular parallelepipeds. In the vicinity of 24% Ga an anomaly occurs in the magnetostriction as well as in the elastic moduli and in the magnitude of their ΔE‐effect, in an apparent conspiracy to maintain the magnetoelastic energy‐constants (b1,2) ‘‘normal.’’ [Work supported by ONR.]