The structure, magnetic and transport properties of Fe3O4 thin films on different substrates by pulsed laser deposition

Abstract

Magnetite thin films (10–300 nm) are deposited on different substrates including single crystals ((0001)-Al2O3, (001)-Si, (110)-SiO2), textured polycrystalline oxide underlayers (ZnO), amorphous glass, at temperature from room temperature to 550 °C by the pulsed laser deposition technique. Strong (111)-texture can be obtained on single crystal Si, SiO2, amorphous glass, and (0001)-textured ZnO layer, no matter whether they have either a huge lattice mismatch or no matching at all with Fe3O4. The film on single crystal Al2O3 (sapphire) shows a (111)-epitaxial structure with a strong in plane compressive strain. The saturated magnetization for magnetite thin films grown on SiO2 and Si substrates can reach 440 emu/cc while the epitaxial films grown on Al2O3 have a magnetization around 310 emu/cc when the film thickness is 40 nm. The substrate-induced strain in the films grown on Al2O3 substrates significantly affects the magnetic anisotropy and the magnetic coupling at the anti-phase boundaries in the films.