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

The magnetic and magnetostrictive properties of Fe/sub 1-x/Ga/sub x/ and Fe/sub 1-x-y/Ga/sub x/Al/sub y/ (a+y<0.3) single crystals were measured under compressive stresses up to 120 MPa and in magnetic fields up to 1 kOe. Values of /spl lambda//sub 100/ exceeding 200 ppm were observed in samples of Fe/sub 83/Ga/sub 17/ from 180 K to room temperature. Only a small monotonic decrease in magnetostriction with temperature was found. On the other hand, /spl lambda//sub 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, /spl cong/1.8 T) and the magnetic anisotropies reduced (K/sub 1//spl cong/10/sup 4/ J/m/sup 3/). Values of the 'stiff' (high magnetic field) Young's modulus, Bulk modulus, Poison's ratio, and elastic constant C/sub 11/-C/sub 12/ for Fe/sub 85/Ga/sub 15/ at room temperature are, respectively, 77 GPa, 111 GPa, 0.38, and 56 GPa.