Measurement of Spin Dynamics in a Layered Nickelate Using X-Ray Photon Correlation Spectroscopy: Evidence for Intrinsic Destabilization of Incommensurate Stripes at Low Temperatures

We study the temporal stability of stripe-type spin order in a layered nickelate with x-ray photon correlation spectroscopy and observe fluctuations on timescales 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 on both 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 as a result of a competition between stripes and superconductivity, hence occurs via loss of both spatial and temporal correlations.

Automated summary

Using x-ray photon correlation spectroscopy, fluctuations in stripe-type spin order of a layered nickelate were observed on timescales of tens of minutes across a wide temperature range. These fluctuations exhibit anomalous temperature dependence, slowing down at intermediate temperatures and speeding up during heating and cooling, reflecting a direct connection with spatial correlations. The decay of nickelate stripe correlations at low temperatures, similar to the competition between stripes and superconductivity in cuprates, occurs through loss of both spatial and temporal correlations.