Abstract
Neutron spectroscopy was applied to study the magnetic interactions of orbitally degenerate Co2+ on a host MgO rocksalt lattice where no long-range spin or orbital order exists. The paramagnetic nature of the substituted monoxide Co0.03Mg0.97O allows for the disentanglement of spin exchange and spin-orbit interactions. By considering the prevalent excitations from Co2+ spin pairs, we extract seven exchange constants out to the fourth coordination shell. An antiferromagnetic next-nearest-neighbor 180 degrees exchange interaction is dominant; however, dual ferromagnetic and antiferromagnetic interactions are observed for pairings with other pathways. These interactions can be understood in terms of a combination of orbital degeneracy in the t(2g) channel and the Goodenough-Kanamori-Anderson rules. Our work suggest that such a hierarchy of exchange interactions exists in transition-metal-based oxides with a t(2g) orbital degeneracy.
Original language | English |
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Article number | 024415 |
Number of pages | 7 |
Journal | Physical Review B |
Volume | 98 |
Issue number | 2 |
DOIs | |
Publication status | Published - 17 Jul 2018 |
Keywords / Materials (for Non-textual outputs)
- MAGNETIC EXCITATIONS
- COBALT OXIDE
- SUPEREXCHANGE INTERACTION
- ISOLATED CLUSTERS
- MIXED-CRYSTALS
- SCATTERING
- IONS
- COO
- ANTIFERROMAGNETISM
- SUSCEPTIBILITY