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Spinel ferrite structures have vast applications, from microwave to radio frequencies. In order to acquire new electronic and optical behavior, divalent cations can be added to normal spinel ferrite structure. This way it is possible to facilitate its usage in material and science technology. In this work we have analyzed the impact of Ca addition to normal spinel manganese ferrite on electronic and magnetic properties by the first-principles calculations. For the exchange-correlation functional, Wu-Cohen, generalized gradient approximation method was used for electron-electron interactions. The calculation of electronic band structures is based on full potential linear augmented plane wave method. The calculated density of states shows that the addition of Ca ions has a significant impacts on the electronic and magnetic structure.

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We have investigated optical properties which are very important for optoelectronic devices, such as laser modulators, photo detectors, optical amplier and high ecient solar cells of BN and BBi using the density functional theory based on full potential linearized augmented plane wave method as implemented in Vienna ab-initio simulation package (VASP). The exchange correlation potential is treated by generalized gradient approximation. Primarily, we have calculated the equilibrium lattice constant (a0) of BN and BBi. Our results for a0 are 3.6264 Å and 5.5243 Å for BN and BBi, respectively. These results fairly coincide with theoretical and experimental studies. Then, we have calculated the optical parameters (dielectric functions, absorption and refractive index, reectivity, energy loss function and conductivity) of BN and BBi which is directly related to the energy band structure of the material.