Bias voltage dependence of the tunneling magneto-resistance of SrTiO3 based magnetic tunnel junctions grown epitaxially on Si (100)

We present data on the magneto-transport properties of epitaxial magnetic tunnel junctions fabricated with SrTiO$_{3}$. These junctions were deposited on silicon $<$100$>$ using pulsed laser and magnetron sputtering techniques. Various ferromagnetic electrode materials were studied. The structures were patterned using in-situ metal shadow masks. Structural and material characterization of these films was performed using x-ray diffraction, SQUID, Auger spectroscopy and transmission electron microscopy. The relationship of the sign of the tunneling magneto-resistance, whether positive or negative, to details of the structures will be presented.