Abstract
We report a combined experimental and theoretical study of the unusual ferromagnetism in the one-dimensional copper-iridium oxide . Utilizing Ir edge resonant inelastic x-ray scattering, we reveal a large gap magnetic excitation spectrum. We find that it is caused by an unusual exchange anisotropy generating mechanism, namely, strong ferromagnetic anisotropy arising from antiferromagnetic superexchange, driven by the alternating strong and weak spin-orbit coupling on the Ir and Cu magnetic ions, respectively. From symmetry consideration, this novel mechanism is generally present in systems with edge-sharing plaquettes and octahedra. Our results point to unusual magnetic behavior to be expected in mixed transition-metal compounds via exchange pathways that are absent in pure or compounds.
- Received 1 February 2013
DOI:https://doi.org/10.1103/PhysRevLett.111.057202
© 2013 American Physical Society