Optical properties of Mn1.56Co0.96Ni0.48O4 films studied by spectroscopic ellipsometry

Spectroscopic ellipsometry is used to determine the optical properties of the noncrystalline and crystalline Mn1.56Co0.96Ni0.48O4 (MCN) films prepared by chemical solution deposition method in the range of 250-1100 nm. A pronounced difference in the optical functions is found between 500 and 600 degrees C. Two distinctive peaks, attributed to the critical points of the MCN films, appear in the optical constant spectra for the films annealed at 600 degrees C while they are not obvious for the films annealed at 500 degrees C. The presented results are instructive, further understanding the physical properties of transition metal oxides in theory.