Microstructure and in-plane component of L1₀-FePt films deposited on MgO and MgAl₂O₄ substrates

Microstructures of FePt films deposited on MgO and MgAl₂O₄ single crystalline substrates were studied using aberration corrected scanning transmission electron microscopy (STEM). The [100] and [010] variants of L1₀-FePt were observed in-the-plane of the FePt grains deposited on the MgAl₂O₄ substrate, which causes in-plane component in magnetization curves. The d-spacing of the (002) planes of L1₀-FePt deposited on MgAl₂O₄ is larger than that deposited on MgO. The reduction of lattice mismatch between FePt and the substrate results in the formation of out-of-plane tensile strain leading to increase in d₀₀₂ and the formation of the in-plane variants in the L1₀-FePt grains.