Valence, spin, and orbital state of Co ions in one-dimensionalCa3Co2O6: An x-ray absorption and magnetic circular dichroism study

Abstract

We have investigated the valence, spin, and orbital state of the Co ions in the one-dimensional cobaltate Ca3Co2O6 using x-ray absorption and x-ray magnetic circular dichroism at the Co-L2,3 edges. The Co ions at both the octahedral Cooct and trigonal Cotrig sites are found to be in a 3+ state. From the analysis of the dichroism we established a low-spin state for the Cooct and a high-spin state with an anomalously large orbital moment of 1.7µB at the Co 3+ trig ions. This large orbital moment along the c-axis chain and the unusually large magnetocrystalline anisotropy can be traced back to the double occupancy of the d2 orbital in trigonal crystal field.

Ferromagnetism in tetragonally distorted LaCoO3 thin films

“…8,5,16 Fig. 3 shows a typical XMCD spectrum of LCO/STO samples grown in 200 mTorr and 10 mTorr of oxygen.…”

Magnetic properties and crystal structure of Sr3CoIrO6and Sr3NiIrOMikhailova1, Schwarz2, Senyshyn3 et al. 2012Phys. Rev. BSelf Cite

“…In principle, one has to be careful in applying the equation Eq. (1) for analyzing the paramagnetic susceptibility and drawing conclusions about the magnitude of magnetic moments and interactions in Co 2+ -containing materials: [15][16][17]30 the degeneracy of the crystal field split states of a d 7 configuration may be lifted by the spin-orbit interaction, leading to nontrivial temperature dependence of the magnetic susceptibility. To what extent this is the case for Sr 3 CoIrO 6 will be subject of a further study looking into the details of the electronic structure of this material.…”

Field-driven magnetisation steps in Ca 3 Co 2 O 6 : A single-crystal neutron-diffraction study

“…In the ab plane the CoO 6 chains are arranged in a triangular lattice with a Co-Co separation of 5.24Å, double that along the chains [2]. Both the cobalt ions are trivalent with alternate high-spin S = 2 and low-spin S = 0 states corresponding to the CoO 6 trigonal prisms and the octahedra respectively [5,[25][26][27]. The intrachain coupling is ferromagnetic (FM) while the interchain coupling is antiferromagnetic (AFM) [3][4][5].…”