Interplay of structural and electronic phase separation in single crystalline La(2)CuO(4.05) studied by neutron and Raman scattering

TL;DR

This study investigates the coexistence and interaction of structural, electronic, and magnetic phases in La(2)CuO(4.05) using neutron and Raman scattering, revealing phase separation, magnetic ordering, and superconducting gap features.

Contribution

It provides new insights into phase separation and interplay between antiferromagnetism and superconductivity in La(2)CuO(4.05) through combined neutron and Raman scattering analysis.

Findings

Presence of two phases up to 300 K indicating phase separation.

Antiferromagnetic order established below 210 K.

Superconducting gap observed below 24 K with phase volume fraction changes.

Abstract

We report a neutron and Raman scattering study of a single-crystal of La(2)CuO(4.05) prepared by high temperature electrochemical oxidation. Elastic neutron scattering measurements show the presence of two phases, corresponding to the two edges of the first miscibility gap, all the way up to 300 K. An additional oxygen redistribution, driven by electronic energies, is identified at 250 K in Raman scattering (RS) experiments by the simultaneous onset of two-phonon and two-magnon scattering, which are fingerprints of the insulating phase. Elastic neutron scattering measurements show directly an antiferromagnetic ordering below a N\'eel temperature of T_N =210K. The opening of the superconducting gap manifests itself as a redistribution of electronic Raman scattering below the superconducting transition temperature, T_c = 24K. A pronounced temperature-dependent suppression of the intensity of the (100) magnetic Bragg peak has been detected below T_c. We ascribe this phenomenon to a change of relative volume fraction of superconducting and antiferromagnetic phases with decreasing temperature caused by a form of a superconducting proximity effect.