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Stabilization of ferromagnetic ordering in cobaltite double perovskites of La 2 CoIrO 6 and La 2 CoPtO 6

2015; IOP Publishing; Volume: 27; Issue: 33 Linguagem: Inglês

10.1088/0953-8984/27/33/336002

1361-648X

Min‐Cheol Lee, Changhee Sohn, Sang Yong Kim, K D Lee, Choongjae Won, N. Hur, Jy Kim, Deok‐Yong Cho, T. W. Noh,

Electronic and Structural Properties of Oxides

We investigated the local electronic structure and magnetic properties of the cobaltite double perovskites La2CoIrO6 and La2CoPtO6 using Co L2,3-edge x-ray absorption spectroscopy and x-ray magnetic circular dichroism. Despite similarity in the local electronic structure (Co(2+) high-spin states) as well as in the crystal structure (P2(1)/n), only La2CoIrO6 exhibits substantial orbital and spin magnetic moments of Co(2+), whereas they are much weaker in the case of La2CoPtO6. This composition dependence is consistent with the results of magnetization measurements. The details of the mechanism of ferromagnetic ordering in the Co(2+) sublattice in La2CoIrO6 and the lack thereof in La2CoPtO6 are explained in terms of the orbital hybridization of the Co minority-spin t(2g) state and the Ir/Pt j(eff) = 1/2 state.