Microstructure and optical properties of pulsed-laser-deposited iron oxide films

We have grown epitaxial iron oxide films on MgO substrates using pulsed laser deposition. In the wavelength range of 0.3-2 /spl mu/m, the refractive index was 2.5/spl plusmn/0.2 and the absorption coefficient was in the range of 5-16 /spl mu/m/sup -1/, with a minimum at a 0.87-/spl mu/m wavelength. Absorption peaks were fitted at 0.33/spl plusmn/0.01 /spl mu/m, 0.54/spl plusmn/0.04 /spl mu/m, and 1.78/spl plusmn/0.15 /spl mu/m wavelengths. The Faraday rotation of the films was 4/spl deg///spl mu/m at 0.645 /spl mu/m and 2.5/spl deg///spl mu/m at 1.55 /spl mu/m. Both the high Faraday rotation and the high absorption, in addition to a significant electrical conductivity, are most probably the result of Fe/sup 2+/ ions present in the /spl gamma/-Fe/sub 2/O/sub 3/ films deposited in vacuum.