Molecular beam epitaxy synthesis and characterization of hexagonal P6₃cm scandium ferrite films

ScFeO₃ is a novel material with increasing interest in the oxide community of material science and engineering. We used molecular beam epitaxy (MBE) to synthesize films of ScFeO₃ with a thickness of 70nm to 80nm, on (0001) oriented Al₂O₃ substrates, to study the material’s expected multiferroic behavior near room temperature. We utilized a shuttering MBE technique where atoms of iron were deposited for a time interval, followed by the deposition of scandium atoms for the same amount of time. The shuttering times were varied between samples to determine the optimal times for the highest degree of phase purity, orientation, and crystalline perfection in the films. The growth was monitored by reflection high energy electron diffraction. The films were characterized by X-ray diffraction, reciprocal space mapping, atomic force microscopy, and variable temperature ultraviolet Raman spectroscopy. Raman spectra show that ScFeO₃ films have a polar hexagonal P6₃cm structure. The temperature evolution of the Raman spectra of a ScFeO₃ films measured in the range 10–1450 K indicate a transition to a non-polar (likely P6₃/mmc) phase; fitting of the temperature dependence of the Raman intensities yields a transition temperature of 950±50 K. The results of characterization of the ScFeO₃ films grown on bottom electrodes of strontium cobalt ruthenate will also be presented.