Parity-dependent proximity effect in superconductor/antiferromagnet heterostructures

TL;DR

This study investigates how the superconducting transition temperature (Tc) in Nb films is affected by the parity of the number of Fe layers in a synthetic antiferromagnet, revealing a parity-dependent proximity effect.

Contribution

It demonstrates a parity-dependent variation of Tc in superconductor/antiferromagnet heterostructures, supported by numerical modeling using Usadel equations.

Findings

Tc peaks at even N and dips at odd N

Good correlation between experimental data and Usadel model

Evidence of dirty limit behavior in the heterostructures

Abstract

We report the effect on the superconducting transition temperature (Tc) of a Nb film proximity coupled to the synthetic antiferromagnet Fe/{Cr/Fe}_(N-1). We find that there is a parity dependence of Tc on the total number of Fe layers, N; locally Tc is always a maximum when N is even, and a minimum when N is odd. The Fe electron mean free path and coherence length are indicative of dirty limit behavior; as such, we numerically model our data using the linearized Usadel equations with good correlation.