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A study is conducted to show that the films grown on MgO (100) substrate remain fully coherent up to much greater thickness than predicted by the FKR model (70 nm) from the strain relaxation studies of epitaxial Fe3O4 thin films grown on MgO (100) substrates. The observed strain relaxation behavior is attributed to the differences in the crystal structure symmetry between MgO and Fe3O4.

The ferromagnetic resonance study is employed to explain the impact of miscut direction on the magnetic anisotropy exhibited by the different magnetite films that are grown on the vicinal MgO(100) compounds. The compound is shown to exhibit in-plane fourfold, as well as uniaxial anisotropies.

X-ray magnetic circular dichroism (XMCD) is used for studying the epitaxial magnetite ([Fe.sub.3][O.sub.4]) films on MgO (001) and [Al.sub.2][O.sub.3] (0001) substrates. The differences observed between film grown on MgO and [Al.sub.2][O.sub.3] are described within the framework of differences in mismatch strain experienced by the films.

The effect of swift heavy ion (SHI) irradiation on structural, electrical transport and magnetic properties of epitaxial magnetite ([Fe.sub.3][O.sub.4]) thin films grown on MgO(100) oriented substrate is investigated. The SHI irradiation is a tool that can be used to modify the various parameters of these materials in a controlled fashion.

The magnetoresistance (MR) studies of magnetite thin films deposited on vicinal MgO substrates demonstrated an enhanced MR along the miscut direction as compared to the direction perpendicular to it. The MR anisotropy increases with the decrease in temperature and peaks at he Verwey transition.

Low frequency conduction noise properties of epitaxial magnetite (Fe3O4) thin films having a varying density of antiphase boundaries were investigated as a function of temperature and frequency. Hooge parameter has a strong thickness dependence at low temperatures, which implies that the antiphase boundaries play an important role in determining the transport mechanism in epitaxial Fe3O4 films.

Abstract: We report on a heat-induced transformation of the surface of α-alumina (0001) crystals which have an off-cut in the [110] direction. Annealing the crystal causes the surface to transform into a regular array of (0001) and (116) facets. The resultant faceted morphology represents the equilibrium state of the system. It is demonstrated that the average terrace periodicity is determined by the annealing temperature. Possible causes for the surface rearrangement are also discussed. This method could be used for producing templates with controlled periodicity for growth of nanostructure arrays. [Copyright &y& Elsevier]

Abstract: We have observed an exchange bias effect on field cooling of epitaxial magnetite, Fe3O4, films on MgO (100) substrates. We attribute this effect to the presence of antiphase boundaries (APBs). Magnitude of the exchange bias field (He) strongly depends on the thermo-magnetic history of the sample. The strength of the He was found to increase with an increase in film thickness and is attributed to the strain driven redistribution of atoms in the vicinity of APBs leading to enhanced antiferromagnetic exchange interactions. [Copyright &y& Elsevier]