Suppression of Superconductivity in YBCO/LCMO Superlattices

TL;DR

This study investigates how magnetic LCMO layers suppress superconductivity in YBCO/LCMO superlattices, revealing that proximity effects distort the superconducting gap and reduce condensate density.

Contribution

It provides experimental evidence of superconductivity suppression due to magnetic proximity effects in YBCO/LCMO superlattices.

Findings

Superconducting condensate density is drastically reduced by magnetic layers.

Superconductivity suppression correlates with proximity effects.

YBCO layer thickness influences the degree of suppression.

Abstract

The competition of superconductivity and magnetism in superlattices composed of alternating YBa$_2$Cu$_3$O$_{7-d}$ and La$_{0.67}$Ca$_{0.33}$MnO$_{3}$ thin films is investigated using low-energy optical spectroscopy. The thickness of the superconducting YBCO layers is varied from 30 nm to 20 nm while the thickness of the magnetic LCMO layers is kept constant at 20 nm. We clearly observe that the superconducting condensate density in the superconducting state of superlattice is drastically reduced by the magnetic subsystem which may be connected with proximity effects that distort the gap symmetry and thus suppress superconductivity.