EBSD analysis of the growth of (0 0 1) magnetite thin films on MgO substrates

Magnetite (Fe₃O₄) thin films grown on (0 0 1) MgO substrates are analyzed by means of electron backscatter diffraction (EBSD) analysis. The EBSD technique enables the crystallographic orientation of individual grains to be determined with a high-spatial resolution up to 20 nm even on ceramic samples. The magnetite films are fully strained due to the lattice mismatch of MgO and Fe₃O₄. Upon annealing in air, the magnetic properties of the magnetite thin films were found to change considerably. Using the EBSD analysis, we find that most of the misorientation boundaries existing in the as-grown films are vanishing after the annealing step and the remaining misoriented grains form small islands with a size of about 100 nm. The size and distribution of these islands correspond well to the observations of antiferromagnetic pinning centers within the magnetic domain structures carried out by magnetic force microscopy on the same samples.