Anelastic spectroscopy study of the spin-glass and cluster spin-glass phases of La$_{2-x}$Sr$_{x}$CuO$_{4}$ $(0.015<x<0.03)$

TL;DR

This study uses anelastic spectroscopy to investigate the transition between spin-glass and cluster spin-glass phases in La$_{2-x}$Sr$_{x}$CuO$_{4}$, revealing phase separation and domain wall dynamics near the critical doping level.

Contribution

It provides experimental evidence of phase separation and domain wall motion in La$_{2-x}$Sr$_{x}$CuO$_{4}$ around the critical doping, supporting recent neutron scattering findings.

Findings

Elastic energy loss shows a step below the freezing temperature in the CSG phase.

Excess dissipation is linked to domain wall motion between spin clusters.

Results support electronic phase separation at certain doping levels.

Abstract

The anelastic spectra of La$_{2-x}$Sr$_{x}$CuO$_{4}$ have been measured at liquid He temperatures slightly below and above the concentration $% x_{c}\simeq 0.02$ which is considered to separate the spin-glass phase from the cluster spin-glass (CSG) phase. For $x\le x_{c}$ all the elastic energy loss functions show a step below the temperature $T_{g}(x=0.02) $ of freezing into the CSG state, similarly to what found in samples well within the CSG phase, but with a smaller amplitude. The excess dissipation in the CSG state is attributed to the motion of the domain walls between the clusters of antiferromagnetically correlated spin. These results are in agreement with the recent proposal, based on inelastic neutron scattering, of an electronic phase separation between regions with $x\sim 0$ and $x\sim 0.02$, at least for $x>0.015$