We report our investigation of the electronic and magnetic excitations of Sr3NiIrO6 by resonant inelastic x-ray scattering at the Ir L3 edge. The intra-t2g electronic transitions are analyzed using an atomic model, including spin-orbit coupling and trigonal distortion of the IrO6 octahedron, confronted to {\it ab initio} quantum chemistry calculations. The Ir spin-orbital entanglement is quantified and its implication on the magnetic properties, in particular in inducing highly anisotropic magnetic interactions, is highlighted. These are included in the spin-wave model proposed to account for the dispersionless magnetic excitation that we observe at 90 meV. By counterbalancing the strong Ni2+ easy-plane anisotropy that manifests itself at high temperature, the anisotropy of the interactions finally leads to the remarkable easy-axis magnetism reported in this material at low temperature.
@article{arxiv.1504.05420,
title = {Anisotropic interactions opposing magnetocrystalline anisotropy in Sr$_3$NiIrO$_6$},
author = {E. Lefrançois and A. -M. Pradipto and M. Moretti Sala and L. C. Chapon and V. Simonet and S. Picozzi and P. Lejay and S. Petit and R. Ballou},
journal= {arXiv preprint arXiv:1504.05420},
year = {2016}
}