Epitaxial lift-off of flexible single-crystal magnetite thin films with tunable magnetic performances by mechanical deformation

Integrating magnetic oxide thin films without restriction of substrates is crucial for their applications in electronic and spintronic devices. Here the water-soluble Sr3Al2O6 (SAO) layer is employed as the sacrificial layer to transfer the millimeter-size single-crystal Fe3O4 films from SrTiO3 (STO) to silicon and flexible PET substrates. Structural characterizations indicate that the transferred films have the same epitaxial quality with the as-grown films. The hysteresis loops measurements of flexible Fe3O4/PET samples show a deceasing magnetic anisotropy under both of convex and concave deformations. Such tunable magnetic anisotropy is confirmed by fitting the angular dependence of ferromagnetic resonance (FMR) fields. These results provide a damage-free way to fabricate single-crystal spinel ferrites films on the selected substrates for flexible spintronic devices.