Glassy nature of stripe ordering in La(1.6-x)Nd(0.4)Sr(x)CuO(4)

TL;DR

This study uses neutron scattering to investigate stripe order and magnetic structures in La(1.6-x)Nd(0.4)Sr(x)CuO(4), revealing a glassy, disordered stripe state with fluctuating spins and temperature-dependent correlations.

Contribution

It provides new insights into the disorder and fluctuation dynamics of stripe order in cuprates through detailed neutron scattering analysis.

Findings

Stripe order shows finite correlation length below 30 K.

Disorder in stripe spacing explains peak width differences.

Incommensurate spin excitations persist above 50 K.

Abstract

We present the results of neutron-scattering studies on various aspects of crystalline and magnetic structure in single crystals of La(1.6-x)Nd(0.4)Sr(x)CuO(4) with x=0.12 and 0.15. In particular, we have reexamined the degree of stripe order in an x=0.12 sample. Measurements of the width for an elastic magnetic peak show that it saturates at a finite value below 30 K, corresponding to a spin-spin correlation length of 200 A. A model calculation indicates that the differing widths of magnetic and (previously reported) charge-order peaks, together with the lack of commensurability, can be consistently explained by disorder in the stripe spacing. Above 30 K, the width of the nominally elastic signal begins to increase. Interpreting the signal as critical scattering from slowly fluctuating spins, the temperature dependence of the width is consistent with renormalized classical behavior of a 2-dimensional anisotropic Heisenberg antiferromagnet. Inelastic scattering measurements show that incommensurate spin excitations survive at and above 50 K, where the elastic signal is neglible. We also report several results related to the LTO-to-LTT transition.