The effect of magnetic field annealing on single crystal iron gallium alloy

In this study, we investigate magnetic field annealing of Fe82.5Ga17.5 single crystal disks with two easy axes ([100] and [010]) in the plane of the disk. Magnetic annealing was conducted with a high magnetic field (H>12 kOe) applied along the [100] or [010] easy axes of the demagnetized, as-grown, slow-cooled sample. Strain measurements were recorded both before and after the magnetic annealing of the samples from a demagnetized state. After each annealing protocol, the resultant built-in uniaxial anisotropy constants were measured using torque magnetometry and also using an approach that calculates anisotropy based on magnetization curves. The built-in anisotropy constant after magnetic annealing strongly depends on annealing protocol. The calculated anisotropy constants determined for each sample show consistent trends for each annealing condition using the two different anisotropy measurement methods. The maximum uniaxial anisotropy constant was 4.24 kJ/m(3) and the built-in effective prestress was -19.9 MPa after field annealing. (C) 2008 American Institute of Physics.