Optical properties of Ti0.5Li0.5La0.1Fe1.9O4 ferrite thin film

High-purity oxide powders are processed together using the standard ceramics technique to form a ferrite material with the composition formula; Ti0.5Li0.5La0.1Fe1.9O4. Thin films varying from 15 to 115 nm are produced by the thermal evaporation technique. The optical properties and optical constants of thin films of various thicknesses have been investigated by means of the transmittance and reflectance spectra. The type of optical transition responsible for optical absorption was indirect transitions. The refractive index and the extinction coefficient of the samples were determined in the visible range as a function of wavelength. The ratio of carrier concentration to electron effective mass (N/m*) and the residual dielectric constant (ε∞) were calculated and their dependence on the film thickness was considered. The refractive index dispersion for the thinner film (15 nm) is discussed in terms of the single oscillator model and the oscillator parameters were determined.