Analysis of cobalt-doped iron oxide thin films by synchrotron radiation

Abstract

Surface and bulk structures of as-deposited Fe 3O 4 and post-oxidized γ-Fe 2O 3 thin films were successfully identified by synchrotron diffraction analysis. A new synchrotron diffraction method which combines the Seemann-Bohlin and the grazing incidence techniques was used to record polycrystalline diffraction patterns for structure depth profiling analysis. The post-oxidized film was found to have an α-Fe 2O 3 layer at the surface and γ-Fe 2O 3 in the bulk of the film. The formation of a thermodynamically stable antiferromagnetic α-Fe 2O 3 surface caused the magnetically dead layer previously detected by neutron reflection analysis. Synchrotron diffraction results also showed that the structure of the as-deposited film remains constant throughout the thickness of the film. The presence of a superlattice (300) peak indicates the film has been oxidized beyond Fe 3O 4.