Effect of Low Substrate Temperature on the Magnetic Properties and Domain Structure of Fe₇₀Ga₃₀ Thin Films

Abstract

We report on the effect of low substrate temperature on the correlation between structure, magnetic properties, and micromagnetic behavior of Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">70</sub> Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">30</sub> thin films. The enhanced grain size and the decrease in the number of pinning centers are in correlation with the enhanced saturation magnetization and domain size (~0.2-0.5 μm), respectively. Estimated effective magnetic anisotropy energy (K <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</sub> ) is found to increase with substrate temperature from 7.5 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> J/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> (room temperature) to 13.6 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> J/m <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> (350 °C). The coercivity variation from the object-oriented micromagnetic framework (OOMMF) simulation is in line with respect to experimental values. Spin structure from simulation also indicates multiple-domain configuration when there is a magnetization reversal.