55~Tesla coercive magnetic field in frustrated Sr$_3$NiIrO$_6$

TL;DR

This study reports the record-high coercive magnetic field of 55 Tesla in Sr$_3$NiIrO$_6$, caused by frustrated antiferromagnetic states and strong magnetocrystalline anisotropy, revealing novel physics from 5d orbital interactions.

Contribution

It demonstrates the largest coercive field observed and uncovers its origin in frustrated antiferromagnetism combined with 5d orbital effects.

Findings

Coercive field of up to 55 T measured in Sr$_3$NiIrO$_6$

The coercive field is due to frustrated antiferromagnetic states and anisotropy

Highlights the role of 5d orbitals in magnetic properties

Abstract

We have measured extremely large coercive magnetic fields of up to 55~T in Sr$_3$NiIrO$_6$, with a switched magnetic moment $\approx 0.8~\mu_{\rm B}$ per formula unit. As far as we are aware, this is the largest coercive field observed thus far. This extraordinarily hard magnetism has a completely different origin from that found in conventional ferromagnets. Instead, it is due to the evolution of a frustrated antiferromagnetic state in the presence of strong magnetocrystalline anisotropy due to the overlap of spatially-extended Ir$^{4+}$ 5$d$ orbitals with oxygen 2$p$ and Ni$^{2+}$ 3$d$ orbitals. This work highlights the unusual physics that can result from combining the extended $5d$ orbitals in Ir$^{4+}$ with the frustrated behaviour of triangular lattice antiferromagnets.