Magnetic circular x-ray dichroism study ofLa1−xSrxCoO3

Abstract

The ferromagnetic oxide ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CoO}}_{3}$ has been studied by magnetic circular x-ray dichroism (MCXD) in core-level absorption. In the Co ${2p}_{3/2,1/2}$ absorption, the orbital and spin magnetic moments of the Co $3d$ are deduced with the use of magneto-optical sum rules and compared with magnetization measurements. In the O $1s$ absorption, large negative MCXD structures are observed, showing that the O $2p$ orbitals are heavily mixed with the Co $3d$ orbitals and that the orbital magnetic moment of O $2p$ is parallel to the orbital magnetic moment of Co $3d$ and the total magnetic moment. The relative magnitudes of the spin and orbital magnetic moments are most consistently interpreted based on the intermediate-spin states of Co $3d$ within the ionic model, although the absolute values of the spin and orbital magnetic moments are found to be smaller, probably indicating that the itinerant electron description of the Co $3d$ states is more appropriate in ${\mathrm{La}}_{1\ensuremath{-}x}{\mathrm{Sr}}_{x}{\mathrm{CoO}}_{3}.$