Magnetostrictive properties of body-centered cubic Fe-Ga and Fe-Ga-Al alloys

The magnetic and magnetostrictive properties of Fe1-xGax and Fe1-x-yGaxAly (x + y < 0.3) single crystals were measured under compressive stresses up to 120 MPa and in magnetic fields up to 1 kOe. Values of (100) exceeding 200 ppm were observed in samples of Fe83Ga17 from 180 K to room temperature. Only a small monotonic decrease in magnetostriction with temperature was found. On the other hand, lambda (111) maintained small negative values close to those of b.c.c. Fe. In all cases, no higher order magnetostrictive terms were detectable. With 15 to 20 atomic percent replacement of Fe by Ga, the magnetizations remain high (M-s congruent to 1.8 T) and the magnetic anisotropies reduced (K-1 congruent to 10(4) J/m(3)). Values of the 'stiff' (high magnetic field) Young's modulus, Bulk modulus, Poison's ratio, and elastic constant c(11)-c(12) for Fe85Ga15 at room temperature are, respectively, 77 GPa, 111 GPa, 0.38, and 56 GPa.