Induced Tetragonal Magnetic Anisotropy in Stress Annealed Galfenol Alloys

In this paper (1) the development of a stress dependent tetragonal (uniaxial to lowest order) anisotropy in the Galfenol (iron-gallium) alloys by stress annealing is described (2) their magnetic, magnetostrictive and anisotropic properties by fitting magnetostriction and magnetoelastic data to a simple magnetization rotation model are given, and (3) the amount of built-in stress by stress annealing is determined. The uniaxial anisotropy, cubic anisotropy, saturation magnetic induction, and saturation magnetostriction were obtained from measurements of the magnetization and magnetostriction of Fe_100-xGa_x, x = 12.5, 18.5 and 22.0 vs. field for various compressive stresses (-100 MPa < T < 0) before and after stress annealing.