Investigation of Hubbard parameter on structural, magnetic and electronic properties of mono ferrite strontium

In this work، the effect of Hubbard parameter on structural، magnetic and electronic properties of SrFe2O4 has been investigated. The calculations have been performed by Full-Potential-Linearized Augmented Plane Wave (FP-LAPW) method in the framework of density functional theory with different approximations about exchange-correlations energy by WIEN2k package. The results indicated that for SrFe2O4، ferrimagnetic is the most stable state and there are six different spin configurations for ferromagnetic. «Generalized Gradient» and «Local Spin Density» Approximations were not appropriate for explaining the expected band gap and magnetic moment of the compound. Therefore، other approximations like GGA+U were used. Band gap and lattice constants improved by using this approximation. In Hubbard approximation، band gap and magnetic moment were calculated per different U parameters and U=4. 5 eV was chosen for future calculations. The effect of pressure on the band gap was calculated and it was found that by increasing pressure، band gap for both spin up and down states increases. Lattice constants results are in consistent with experimental studies. However، the amount for bulk modulus، magnetic moment and band gap have not been reported experimentally.