Structural and magnetic characterization of Fe₃O₄/Mn₃O₄ superlattices

High-quality ferrimagnetic superlattices Fe₃O₄/Mn₃O₄ were grown on MgO(0 0 1) substrates by molecular beam epitaxy. The modulation coherency and interface sharpness are characterized by reflection high-energy electron diffraction and X-ray diffraction. Magnetization as a function of the applied field (50 kOe) and temperature (20-300 K) was measured. The magnetic response shows strong dependence on the modulation wavelength. A combined single magnetic transition temperature is predicted to be approximately 600 K for samples with modulation wavelength <43 angstroms. An abrupt decrease of the magnetization is found below 50 K for some superlattices. This feature may be induced by the anisotropic energy related to the tetragonal symmetry of Mn₃O₄.