Influence of miscut direction on magnetic anisotropy of magnetite films grown on vicinal MgO (100)

Abstract

Ferromagnetic resonance (FMR) was used to study the influence of miscut direction on the in-plane fourfold and uniaxial magnetic anisotropies of epitaxial Fe3O4 films grown on vicinal MgO (100) surfaces. In-plane angular dependent measurements at room temperature on Fe3O4 films on two different miscut directions (miscut along ⟨011⟩ and ⟨010⟩ directions) of MgO showed the presence of both in-plane fourfold (cubic) and in-plane uniaxial anisotropies. Temperature dependent FMR investigations show that the in-plane fourfold anisotropy constant (K4) is approximately the same for both samples at room temperature. The magnitude of K4 increases gradually with decreasing temperature and changes sign from negative to positive values at 130 K. This behavior is consistent with that of bulk magnetite. In addition to K4, we find an additional uniaxial component (K2), whose strength is quite different for the different miscut directions. The magnitude of K2 shows very little or no temperature dependence. The observed differences in the magnitude of K2 with miscut directions are related to the changes in the antiphase boundary structure and altered magnetic configurations at the boundaries.