Granular superconductivity and magnetic-field-driven recovery of macroscopic coherence in a cuprate/manganite multilayer

TL;DR

This study demonstrates that in PLCMO/YBCO multilayers, the low-temperature superconducting state of YBCO is granular and can be restored by a magnetic field that suppresses charge-orbital order in PLCMO, revealing a coupling between these phenomena.

Contribution

It uncovers the magnetic-field-driven recovery of macroscopic coherence in YBCO, linking it to the suppression of charge-orbital order in PLCMO in multilayer structures.

Findings

YBCO exhibits a granular superconducting state at low temperatures.

A magnetic field restores superconducting coherence in YBCO.

Charge-orbital order in PLCMO influences the superconducting state of YBCO.

Abstract

We show that in Pr$ _{0.5} $La$ _{0.2} $Ca$ _{0.3} $MnO$ _{3} $/YBa$ _{2} $Cu$ _{3} $O$ _{7} $ (PLCMO/YBCO) multilayers the low temperature state of YBCO is very resistive and resembles the one of a granular superconductor or a frustrated Josephson-junction network. Notably, a coherent superconducting response can be restored with a large magnetic field which also suppresses the charge-orbital order in PLCMO. This coincidence suggests that the granular superconducting state of YBCO is induced by the charge-orbital order of PLCMO. The coupling mechanism and the nature of the induced inhomogeneous state in YBCO remain to be understood.