Giant Mutual Proximity Effects in Ferromagnetic/Superconducting Nanostructures

TL;DR

This paper reports strong mutual proximity effects in ferromagnetic/superconducting nanostructures, with conductance enhancements and re-entrant behavior influenced by magnetic fields, challenging existing theoretical predictions.

Contribution

It presents experimental evidence of unexpectedly large proximity effects and re-entrant superconductivity in Ni/Al nanostructures, supported by a developed numerical analysis.

Findings

Proximity-induced conductance exceeds theoretical predictions by over two orders of magnitude.

Re-entrant superconductivity observed at low magnetic fields.

New peaks in differential resistance linked to saturation magnetization.

Abstract

A strong mutual influence of superconductors (S) and ferromagnetic (F) conductors in hybrid F/S (Ni/Al) nanostructures is observed. The magnitude of a proximity-induced conductance on the F-side is more than two orders larger than that predicted by theory. Re-entrance of the superconductors to the normal state reciprocated by changes on the F-side has been found in low applied magnetic fields with new peaks in the differential resistance as an effect of the saturation magnetisation. An analysis has been developed providing a base for a numerical description of the system. PACS numbers: 74.50.+r, 74.80.Fp, 85.30St