An investigation was made of the crystalline quality of an epitaxially grown γ-Fe2O3 (001) film on a MgO (001) substrate. The interdiffusion of Mg and Fe were also studied by using Rutherford back-scattering spectrometry and channelling methods. The channelling effect in the film appeared to be reduced as compared to that in an ideal single crystal. The minimum yield for Fe was found to range from 16 to 18%. Growth at a substrate temperature of 450C promoted limited Mg out-diffusion into the film. Subsequent annealing resulted in further Mg out-diffusion, which increased in extent with increasing temperature. A minimum of 4at%Mg was detected throughout the film at temperatures below the onset of Fe in-diffusion at 800C. This impurity cation concentration was comparable to the native vacancy concentration in Fe2O3 (4.8at%), and suggested that Mg occupied cation vacancy sites; as already established by Auger electron diffraction measurements. The Mg concentration in the film was 8at%, while the associated Fe concentration in the substrate was 3.4at% after annealing at 800C. The cation impurities were uniformly distributed throughout the film and substrate, with the substitutional fraction in both cases being greater than 90% at lower temperatures.

Rutherford Backscattering and Channelling Studies of Mg and Fe Diffusion at the Interface of Fe2O3/MgO. S.Thevuthasan, W.Jiang, D.E.McCready, S.A.Chambers: Surface and Interface Analysis, 1999, 27[4], 194-8