Structural, electronic and magnetic properties of Fe, Co, Mn-doped GaN and ZnO diluted magnetic semiconductors

Abstract

We performed first-principles spin polarized computations to study the structural, electronic, and magnetic properties of diluted magnetic semiconductors (DMSs) based on wide band-gap wurtzite ZnO and GaN semiconductors doped with transition magnetic metals. The main feature of the resulting DMSs is the strong ferromagnetic spin–spin interaction. We characterzie the gaint Zeeman effect observed experimentally upon applying an external magnetic field using pure quantum mechanical based technique. We found that this effect increases substantially with Fe content in GaN:Fe3+ DMS system at an external magnetic field of 10T. We found that the magnetization of ZnO and GaN doped with Mn3+, Mn2+, Co2+ and Fe3+ is well described by the Brillouin function. The p–d exchange integrals α and β for these transition magnetic ions doped wide band-gap DMSs have been determined accurately. They exhibit positive value for Ga1−xMnxN and Ga1−xFexN and Zn1−xCoxO indicating ferromagnetic interaction. Furthermore, Magnetocrystalline anistropy energy (MAE) and perpinduclar magnetocrystalline anistropy (PMCA) of ZnO:Mn3+, GaN:Fe3+, and ZnO: Co2+ diluted systems for transition ion concentration fixed at x=0.125 have been calculated and discussed based on spin-dependent band structure and density of states calculations. We found a robustness of PMCA with respect to lattice strain is remarakable for all the three DMSs systems studied. We found that ZnO:Mn3+ DMS is a good spin injector.