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

Alessandro Ricci,Christoph Trabant,Marcel Buchholz,Nicola Poccia,James C T Lee,Agustinus Agung Nugroho,Alexey Zozulya,Sujoy Roy,Markus Braden,Gaetano Campi,Jeroen B Goedkoop,Bo Shi,Christian Schüßler-Langeheine,Michael Sprung,Jens Viefhaus,Shrawan Mishra,Leonard Müller,Boby Joseph

doi:10.1103/physrevlett.127.057001

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 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.

Highlights

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
To learn how stripe order decays on cooling when superconductivity as competing phase is absent, we study for a nickelate system spatial and temporal correlations of spin stripes
Possible scenarios that could explain the observed behavior of a loss of integrated intensity and correlation length at low temperatures are (a) the total stripe ordering is shrinking toward low temperatures via the formation of regions that are disordered or have a completely different kind of order or (b) defects form within the stripe-ordered patches that either reduce the ordered volume or imply a spatial phase shift, which, by destructive interference, reduces the diffracted intensity

Summary

Introduction

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. A low-temperature decay of stripe order very much resembling what occurs in cuprates when superconductivity sets in can be observed in x-ray diffraction experiments from nonsuperconducting layered nickelates with doping levels < 1=3: At low temperatures the characteristic superstructure peaks reflecting spin and charge order

Results

Conclusion