Spin Dynamics in an Ordered Stripe Phase

TL;DR

This study investigates low-energy spin excitations in the stripe-ordered phase of La(2)NiO(4+d), revealing dispersion characteristics and persistent incommensurate peaks, with implications for understanding related cuprate superconductors.

Contribution

It provides detailed measurements of spin dynamics in stripe-ordered nickelates, highlighting similarities with cuprate superconductors and advancing understanding of stripe correlations.

Findings

Spin-wave-like excitations disperse from incommensurate points

Incommensurate peaks persist above magnetic transition temperature

Paramagnetic scattering shows signs of stripe correlations

Abstract

Inelastic neutron scattering has been used to measure the low-energy spin excitations in the ordered charge-stripe phase of La(2)NiO(4+d) with d=0.133. Spin-wave-like excitations disperse away from the incommensurate magnetic superlattice points with a velocity ~60% of that in the d=0 compound. Incommensurate inelastic peaks remain well-resolved up to at least twice the magnetic ordering temperature. Paramagnetic scattering from a d=0.105 sample, which has a N\'eel-ordered ground state, shows anomalies suggestive of incipient stripe correlations. Similarities between these results and measurements on superconducting cuprates are discussed.