# Direct Visualization of Spatial inhomogeneity of Spin Stripes Order in La1.72Sr0.28NiO4

## TL;DR

This study visualizes the nanoscale inhomogeneity of spin stripe order in La1.72Sr0.28NiO4 using micro X-ray diffraction, revealing complex phase separation and large spatial fluctuations in spin-density-wave puddles.

## Contribution

It provides the first direct spatial mapping of spin stripe inhomogeneity in La1.72Sr0.28NiO4 at nanoscale, highlighting multiscale phase separation.

## Key findings

- Nanoscale spin-density-wave puddles form with large spatial fluctuations.
- Spin puddles are disconnected by regions with different stripe orientations.
- Multiscale phase separation extends from nanoscale to micron scale.

## Abstract

In several strongly correlated electron systems, defects, charge and local lattice distortions are found to show complex inhomogeneous spatial distributions. There is growing evidence that such inhomogeneity plays a fundamental role in unique functionality of quantum complex materials. La1.72Sr0.28NiO4 is a prototypical strongly correlated material showing spin striped order associated with lattice and charge modulations. In this work we present the spatial distribution of the spin organization by applying micro X-ray diffraction to La1.72Sr0.28NiO4, mapping the spin-density-wave order below the 120K onset temperature. We find that the spin-density-wave order shows the formation of nanoscale puddles with large spatial fluctuations. The nano-puddle density changes on the microscopic scale forming a multiscale phase separation extending from nanoscale to micron scale with scale-free distribution. Indeed spin-density-wave striped puddles are disconnected by spatial regions with different stripe orientation or negligible spin-density-wave order. The present work highlights the complex nanoscale phase separation of spin stripes in nickelate perovskites and opens the question of the energetics at domain interfaces

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Source: https://tomesphere.com/paper/1905.02124