Correlation induced half-metallicity in a ferromagnetic single-layered compound: Sr₂CoO₄

الأصل · EN

The electronic and magnetic properties of Sr₂CoO₄ compound have been studied using ab initio electronic structure calculations. As opposed to GGA calculation, which gives ferromagnetic metallic solution, GGA+U calculations provide two kind of ferromagnetic solutions: (i) half-metallic and (ii) metallic. The half-metallic solution is a ground state of the system and the metallic one is a metastable state. The strong hybridization between Co 3d and O 2p orbitals decides the electronic and magnetic properties of the compound. The total magnetic moment per formula unit is found to be 3 μB (S = 3/2). Our calculations give the magnetocrystalline anisotropy energy of 2.7 meV, which provides a good description of experimentally observed large magnetocrystalline anisotropy. The Heisenberg exchange parameters up to fourth nearest neighbours are also calculated. The mean-field theory gives the TC = 887 K. The possible physical implications of the ferromagnetic half-metallic ground state are also discussed.