Evolution of magnetic oxygen states in Sr-doped LaCoO 3
Date
2012
Authors
Medling, Scott
Lee, Y.
Zheng, H.
Mitchell, J.F.
Freeland, J.W.
Harmon, B.N.
Bridges, F.
Journal Title
Journal ISSN
Volume Title
Publisher
American Physical Society
Abstract
Magnetism in La 1-xSr xCoO 3 as a function of doping is investigated with x-ray absorption spectroscopy and x-ray magnetic circular dicrhoism 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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Keywords
Keywords: Ferromagnetic clusters; First principles electronic structure; Magnetic state; Nonmagnetic groundstates; Nonmagnetic insulating matrix; O K-edges; Oxygen atom; Pseudocubic structure; Rhombohedral distortion; Sr doping; Supercell calculations; Cobalt compo
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Source
Physical Review Letters
Type
Journal article
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2037-12-31
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