
In this article the effect of temperature on optical properties of nano crystalline ceramic Ferromanganese nickel zinc oxide Fe2Mn2Ni2Zn2O11 were studied. Using the Tauc model, the absorption spectrum method was applied to estimate the optical band gap. The sample was synthesized thermo chemically by solid state method at different treating temperatures. A characteristic feature of all solid-state reactions is that they involve the formation of product phase(s) at the interfaces of the reactants. UV-VIS analysis of the sample was carried out. The optical constants of refractive index, extinction coefficient, normal-incidence reflectivity, and absorption coefficient showed systematic variation with temperature. From these data the absorption coefficient was calculated and the band gap energy determined. Using the Wemple- Di Domenico single-oscillator model the dispersion of refractive index was analyzed.