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

2010/01/09 by Sudhir K. Pandey
Physics and Astronomy · #cond-mat.str-el

paper · pdf · doi:10.1103/physrevb.81.035114

published as Phys. Rev. B 81, 035114 (2010) · 7 pages, 5 figures and 2 tables (to appear in Phys. Rev. B)

Abstract

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 μ_B (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 T_C = 887 K. The possible physical implications of the ferromagnetic half-metallic ground state are also discussed.

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