Scale-invariant magnetic textures in the strongly correlated oxide NdNiO$_3$

TL;DR

This study uses advanced X-ray scattering techniques to visualize and analyze scale-invariant, fractal-like antiferromagnetic textures in NdNiO$_3$, revealing critical behavior and robustness of magnetic domains in strongly correlated oxides.

Contribution

It introduces a novel application of resonant magnetic X-ray scattering nanoprobes to directly image magnetic textures at sub-100 nm resolution in NdNiO$_3$, uncovering scale-invariant and fractal magnetic domain structures.

Findings

Discovered robust, nonvolatile magnetic textures after thermal erasure.

Identified scale-free distribution and fractal geometry of antiferromagnetic domains.

Linked magnetic textures to the proximity of a critical point in the system.

Abstract

Strongly correlated quantum solids are characterized by an inherently granular electronic fabric, with spatial patterns that can span multiple length scales in proximity to a critical point. Here, we used a resonant magnetic X-ray scattering nanoprobe with sub-100 nm spatial resolution to directly visualize the texture of antiferromagnetic domains in NdNiO$_3$. Surprisingly, our measurements revealed a highly textured magnetic fabric, which is shown to be robust and nonvolatile even after thermal erasure across its ordering ($T_{N\acute{e}el}$) temperature. The scale-free distribution of antiferromagnetic domains and its non-integral dimensionality point to a hitherto-unobserved magnetic fractal geometry in this system. These scale-invariant textures directly reflect the continuous nature of the magnetic transition and the proximity of this system to a critical point. The present study not only exposes the near-critical behavior in rare earth nickelates but also underscores the potential for novel X-ray scattering nanoprobes to image the multiscale signatures of criticality near a critical point.