Ferromagnetic/superconducting proximity effect in La0.7Ca0.3MnO3 / YBa2Cu3O7 superlattices

TL;DR

This study investigates how ferromagnetic and superconducting layers interact in YBCO/LCMO superlattices, revealing a longer-than-expected proximity effect that depresses superconductivity over larger magnetic layer thicknesses.

Contribution

It provides experimental evidence of the proximity effect in high-Tc superlattices and shows that superconductivity persists at smaller YBCO thicknesses in the presence of magnetic layers.

Findings

Superconductivity is depressed in YBCO when adjacent to LCMO layers.

Superconductivity survives in YBCO at smaller thicknesses due to its short coherence length.

The magnetic layer affects superconductivity over a longer length scale than predicted by existing theories.

Abstract

We study the interplay between magnetism and superconductivity in high quality YBa2Cu3O7 (YBCO) / La0.7Ca0.3MnO3(LCMO)superlattices. We find evidence for the YBCO superconductivity depression in presence of the LCMO layers. We show that due to its short coherence length superconductivity survives in the YBCO down to much smaller thickness in presence of the magnetic layer than in low Tc superconductors. We also find that for a fixed thickness of the superconducting layer, superconductivity is depressed over a thickness interval of the magnetic layer in the 100 nm range. This is a much longer length scale than that predicted by the theory of ferromagnetic/superconducting proximity effect.