Lattice template effect on epitaxial γ-Fe2O3 films prepared by metal organic deposition

The preparation of gamma-Fe2O3 epitaxial films by metal organic deposition and the magnetic properties of the resultant films were studied using two different substrates; MgO and Si. The film deposited on a Si substrate had a polycrystalline corundum structure and did not exhibit magnetic properties, and was thus concluded to be antiferromagnetic alpha-Fe2O3. However, the film deposited on a MgO substrate had the epitaxial spinel structure and exhibited ferromagnetism with a magnetic moment of approximately 2 mu(B) at low temperature, and was thus concluded to be ferromagnetic gamma-Fe2O3. The films and their characteristics are largely dependent on the substrates employed, even when the same preparation conditions are used, such as annealing temperature and atmosphere. The lattice template effect of the substrate is important, especially for the materials with characteristics that are largely dependent on their lattice structure. (C) 2010 American Institute of Physics. [doi:10.1063/1.3309770]