Fe $_{3}$O $_{4}$/MgO/Fe Heteroepitaxial Structures for Magnetic Tunnel Junctions

In this work we report the growth and structural and magnetic characterization of heteroepitaxial Fe$_{3}$ O$_{4}$ /MgO/Fe junctions. All three layers have been deposited by pulsed laser deposition. Combining High Resolution Transmission Electron Microscopy and X-ray results, we have obtained for the heterostructure the epitaxy relation MgO(001) [100]//Fe$_{3}$ O$_{4}$ (001)[100]/MgO(001) [100]/Fe(001)[110]. All interfaces appear very sharp with relatively small root-mean square (rms) roughness, ${\sim}$ 0.2 nm. The magnetic coupling between Fe$_{3}$O$_{4}$ and Fe electrodes is also very small, $J \sim $ 0.03 mJ/m$^{2}$ (MgO barrier thickness of 2 nm). Microfabrication of Magnetic Tunnel Junctions from these heterostructures is in progress.