Nature of the Magnetic Interactions in Sr$_3$NiIrO$_6$

TL;DR

This paper investigates the magnetic interactions in Sr$_3$NiIrO$_6$, revealing how anisotropic exchange influences its strong magnetic anisotropy through theoretical calculations and spectral predictions.

Contribution

It provides a detailed theoretical analysis of the magnetic interactions and anisotropy in Sr$_3$NiIrO$_6$, highlighting the role of anisotropic symmetric exchange.

Findings

Reproduces magnon spectra of Sr$_3$NiIrO$_6$

Identifies signatures differentiating anisotropic exchange from single-ion anisotropy

Elucidates the role of anisotropic symmetric exchange in magnetic anisotropy

Abstract

Iridates abound with interesting magnetic behaviours because of their strong spin-orbit coupling. Sr$_3$NiIrO$_6$ brings together the spin-orbital entanglement of the Ir$^{4+}$ ion with a 3$d$ Ni cation and a one-dimensional crystal structure. It has a ferrimagnetic ground state with a 55 T coercive field. We perform a theoretical study of the magnetic interactions in this compound, and elucidate the role of anisotropic symmetric exchange as the source of its strong magnetic anisotropy. Our first-principles calculations reproduce the magnon spectra of this compound and predict a signature in the cross sections that can differentiate the anisotropic exchange from single-ion anisotopy.