Cooperative coupling of static magnetism and bulk superconductivity in the stripe phase of La_2-xBa_xCuO_4: Pressure- and doping-dependent studies

TL;DR

This study reveals that static spin-stripe order and superconductivity in La_2-xBa_xCuO_4 are closely linked, with pressure tuning their coexistence and revealing a cooperative relationship in the stripe phase of cuprates.

Contribution

It demonstrates the pressure-dependent coexistence and near-coincidence of magnetic order and superconductivity, providing new insights into their interplay in stripe-ordered cuprates.

Findings

Static spin-stripe order exists across the phase diagram.

Pressure induces a transition to a disordered magnetic state.

Superconductivity and magnetic order nearly coincide under pressure.

Abstract

Static spin-stripe order and superconductivity were systematically studied in La_2-xBa_xCuO_4 (0.11 - 0.17) at ambient pressure by means of magnetization and muSR experiments. We find that all the investigated La_2-xBa_xCuO_4 samples exhibit static spin-stripe order and that the quasi two-dimensional superconducting (SC) transition temperature T_c1 and the static spin-stripe order temperature T_so have very similar values throughout the phase diagram. Moreover, the magnetic and the SC properties of the x = 0.155 (LBCO-0.155) and x = 0.17 (LBCO-0.17) samples were studied under hydrostatic pressure. As a remarkable result, in these bulk cuprate superconductors the three-dimensional SC transition temperature T_c and T_so nearly coincide at all pressure investigated (0 - 2.3 GPa). We also observed a pressure induced transition from long-range spin stripe order to a disordered magnetic state at 1.6 GPa in LBCO-0.155, coexisting with a SC state with substantial superfluid density. In LBCO-0.17 a disordered magnetic state is present at all p. The present results indicate that static magnetic order and SC pairing correlations develop in a cooperative fashion in La_2-xBa_xCuO_4, and provide a new route of understanding the complex interplay between static magnetism and superconductivity in the stripe phase of cuprates.