Oriented growth of Fe₃O₄thin film on crystalline and amorphous substrates by pulsed laser deposition

Abstract

We have deposited magnetite thin films using the pulsed laser deposition technique from a α-Fe2O3 target on different substrates (Si (1 1 1), GaAs (1 0 0), Al2O3 (0 0 1) and amorphous float glass (FG)) without any buffer layer at a substrate temperature of 450 °C. These films have been characterized by x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, ac magnetic susceptibility and four-probe resistivity. The XRD results of these films show highly (1 1 1) oriented growth and single phase nature of Fe3O4 films on all substrates. Fe 2p core level x-ray photoelectron spectra and Raman spectra reveal the formation of Fe3O4 throughout the thickness of the films. All films show a Verwey transition at or around 120 K. It is observed that the oriented growth of Fe3O4 films takes place along the [1 1 1] direction on these substrates, which have either a huge lattice mismatch or no matching at all (as in FG) with Fe3O4.