Fe3O4 films grown by laser ablation on Si(100) and GaAs(100) substrates with and without MgO buffer layers

Fe3O4 films have been grown by laser ablation on (100) oriented Si and GaAs substrates. Optimal growth of Fe3O4 was obtained at a substrate temperatur e of 450 degrees C in a molecular oxygen atmosphere of 10(-4) Torr. X-ray m easurements show these films to be (111) oriented, with the growth directio n random in the plane of the film. The introduction of (100) oriented, epit axial MgO buffer layers as thin as 10 Angstrom on the substrates results in the growth of (100) oriented, epitaxial Fe3O4 films. X-ray pole-figure mea surements on these films indicate that both the Fe3O4 and the MgO films are oriented cube on cube on the Si and GaAs substrates, namely (100) (film) p arallel to (100)(substrate). Room-temperature magnetization measurements of the (111) oriented films show that there is good agreement between the mag netic properties of the films grown on Si and on the GaAs substrates. Simil ar agreement is found for the magnetization measurements of the (100) orien ted epitaxiaL. films grown with a MgO buffer layer. Moreover, the hysteresi s loops for the (111) and (100) oriented films are very similar, indicating that the epitaxy has not significantly improved the magnetic properties of the Fe3O4. In fact, a small decrease of the high-field magnetization is ob served with increasing MgO film thickness.