Ab initio calculation of electric field gradient and magnetic hyperfine field in Fe-doped SnO₂

Ab initio calculations of the magnetic and electric hyperfine fields and the magnetic moments were performed for the Fe doped SnO₂ dilute magnetic semiconductors with the Wien2k code embodying the full-potential linearized augmented plane-wave method. The calculated results for the neutral system and the different charged state systems with and without the oxygen vacancy show clearly that the ground state is all magnetic and that the addition of electrons and the appearance of oxygen vacancy can increase the magnetic moment and the magnetic hyperfine field and reduce the electric hyperfine field. The energy level splitting of the Fe-3d orbit can lead to enhancing the magnetic moment and, therefore, a very large magnetic moment of 5 μ_B is obtained for the Sn₁₅Fe¹⁻O₃₂ charged system