Observation of New Incommensurate Magnetic Correlations at the Lower Critical Concentration for Superconductivity (x=0.05) in La(2-x)Sr(x)CuO4

TL;DR

This study uses neutron scattering to investigate magnetic correlations in La(2-x)Sr(x)CuO4 near the critical doping level, revealing unique incommensurate magnetic peaks at x=0.05 that differ from those in the superconducting phase.

Contribution

It reports the discovery of new incommensurate magnetic correlations at the critical doping level, distinct from those in the superconducting phase, highlighting a transition in magnetic behavior.

Findings

Elastic magnetic peaks at all doping levels studied.

Maximum peak linewidth at the critical concentration x=0.05.

Unique rotated incommensurate peaks observed only at x=0.05.

Abstract

Neutron-scattering experiments have been performed on lightly-doped La(2-x)Sr(x)CuO4 single crystals in both the insulating (x=0.03,0.04,0.05) and superconducting (x=0.06) regions. Elastic magnetic peaks are observed at low temperatures in all samples with the maximum peak linewidth occuring at the critical concentration x_c=0.05. New incommensurate peaks are observed only at x=0.05, the positions of which are rotated by 45 degrees in reciprocal space about (pi,pi) from those observed for x>=0.06 in the superconducting phase.