Synchrotron X-ray Analysis of the MBE-Grown Fe3O4 Epilayer on MgO (001)

Making use of high-resolution X-ray diffraction, we characterized an MBE-grown Fe3O4 epilayer on MgO (001) substrate and determined the thickness to be 793 A with the lattice constants a = b = 8.413 ± 0.013 A, c 8.366 ± 0.001 A. Compared to the MgO lattice constant, as= 4.213 A, this Fe3O4 layer was coherently strained on the substrate. Regarding the electronic structure, the DANES spectrum of Fe3O4 (115) revealed more apparent features of the resonant excitation through the electronic quadrupole transition than the case of (004) diffraction, while RXS spectra of the forbidden (002) reflection revealed similar resonance features from room temperature down to 90 K. We conclude that (hhl) diffraction and the associated forbidden reflections with h ≠ 0 would be a better choice to explore the origin of the Verwey transition in magnetite.