Diamagnetic Response of Normal-metal -- Superconductor Double Layers

TL;DR

This paper investigates the magnetic response of superconductor-normal metal sandwiches using quasiclassical theory, explaining experimental observations of diamagnetic behavior and hysteresis beyond the Ginzburg-Landau regime.

Contribution

It provides a theoretical framework for the magnetic response of proximity-coupled superconductor-normal metal layers, including nonlinear effects and hysteresis, aligning with experimental data.

Findings

Magnetization fits experimental low-temperature data.

Hysteretic behavior exists outside Ginzburg-Landau region.

Nonlinear response is characterized at finite magnetic fields.

Abstract

The magnetic response of a proximity-coupled superconductor-normal metal sandwich is studied within the framework of the quasiclassical theory. The magnetization is evaluated for finite values of the applied magnetic field (linear and nonlinear response) at arbitrary temperatures and is used to fit recent experimental low-temperature data. The hysteretic behavior predicted from a Ginzburg-Landau approach and observed in experiments is obtained within the quasiclassical theory and shown to exist also outside the Ginzburg-Landau region.