Measurement of spin dynamics in a layered nickelate using x-ray photon correlation spectroscopy: Evidence for intrinsic destabilization of incommensurate stripes at low temperatures

TL;DR

This study investigates the stability of stripe-like spin order in a layered nickelate using x-ray photon correlation spectroscopy, revealing temperature-dependent fluctuations and intrinsic destabilization of incommensurate stripes at low temperatures.

Contribution

It provides the first direct measurement of spin stripe dynamics in a layered nickelate, showing how fluctuations vary with temperature and spatial correlations.

Findings

Stripe fluctuations slow down at intermediate temperatures

Fluctuations speed up upon heating and cooling

Low-temperature decay involves loss of spatial and temporal correlations

Abstract

We study the temporal stability of stripe-type spin order in a layered nickelate with X-ray photon correlation spectroscopy and observe fluctuations on time scales of tens of minutes over a wide temperature range. These fluctuations show an anomalous temperature dependence: they slow down at intermediate temperatures and speed up both upon heating and cooling. This behavior appears to be directly connected with spatial correlations: stripes fluctuate slowly when stripe correlation lengths are large and become faster when spatial correlations decrease. A low-temperature decay of nickelate stripe correlations, reminiscent of what occurs in cuprates due to a competition between stripes and superconductivity, hence occurs via loss of both spatial and temporal correlations.