Temperature dependence of Mn_(1.56)Co_(0.96)Ni_(0.48)O_4 thin films optical properties by spectroscopic ellipsometry

摘要

The optical properties of spinel Mn_(1.56)Co_(0.96)Ni_(0.48)O_4 thin films have been investigated by spectroscopic ellipsometry in the temperature range from 20 to 260 ℃. By fitting the measured ellipsometric parameter data with a three-layer model by Tauc-Lorentz oscillator dispersion formula, the refractive index and extinction coefficient of the thin films are determined in the spectral range of 280-850 nm. The refractive index decreases in the short-wavelength region but increases in the long-wavelength region with increasing temperature. The extinction coefficient increases with increasing temperature in all visible region.