PLD growth of stoichiometric Fe3O4 thin films for spin tunneling devices

Epitaxial thin Alms of Fe-3-O-delta(4) were prepared on (100) MgO substrates by pulsed laser deposition. These films had a smooth surface on an atomic scale along with extremely high crystalline quality. It was found from the resistivity and XPS measurements that thin films of nearly stoichiometric Fe3O4 are obtained at 300 degrees C in oxygen pressure of 1 x 10(-6) Torr and the conditions for growing the stoichiometric Fe3O4 thin film lie in a narrow range. In addition, it was indicated that low temperature deposition below 200 degrees C is required for the insulating oxide layer onto the Fe3O4 layer in the fabrication process of the tunneling junctions even at oxygen pressure as small as 1 x 10(-5) Torr.