Transport mechanisms in manganite-titanate heterojunctions

We have found that the current-voltage characteristics of La(0.7)Sr(0.3)MnO(3(-delta))/Nb:SrTiO(3) rectifying junctions are quantitatively well described by (thermally assisted) tunneling with an effectively temperature-independent Schottky barrier under no magnetic field, while those of the oxygen deficient junction remarkably deviate from such a simple behavior as magnetic field is applied. These results indicate the junction magnetoresistance arising from magnetic-field changes of the interface band diagram via the strong electron-spin coupling in manganites.