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arXiv · 1210.3396

Evolution of magnetic oxygen states in Sr-doped LaCoO$_3$

S. Medling·Y. Lee·H. Zhang·J. F. Mitchell·J. W. Freeland·B. N. Harmon·F. Bridges
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Abstract

Magnetism in La$_{1-x}$Sr$_x$CoO$_3$ as a function of doping is investigated with X-ray absorption spectroscopy and X-ray magnetic circular dichroism at the O K edge, and corresponding first principles electronic structure calculations. For small x, the spectra are consistent with the formation of ferromagnetic clusters occurring within a nonmagnetic insulating matrix. Sr-induced, magnetic O-hole states form just above E$_F$ and grow with increasing Sr doping. Density functional calculations for x = 0 yield a nonmagnetic ground state with the observed rhombohedral distortion and indicates that doping introduces holes at the Fermi level in magnetic states with significant O 2p and Co t$_{2g}$ character for the undistorted pseudocubic structure. Supercell calculations show stronger magnetism on oxygen atoms having more Sr neighbors.

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S. Medling, Y. Lee, H. Zhang, J. F. Mitchell, J. W. Freeland, B. N. Harmon, F. Bridges. 2012-10-11. Evolution of magnetic oxygen states in Sr-doped LaCoO$_3$. https://doi.org/10.1103/physrevlett.109.157204

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