Reentrance and Magnetic-Field-Induced Superconductivity with Kondo Impurities: Bulk and Proximity Systems

TL;DR

This paper presents a unified framework explaining reentrant superconductivity and magnetic-field-induced superconductivity in systems with Kondo impurities, including their effects in bulk and proximity systems.

Contribution

It introduces a simple, generalized model that accounts for reentrant behavior and magnetic-field-induced superconductivity caused by Kondo impurities in various superconducting systems.

Findings

Reentrant behavior explained by Kondo impurity effects.

Magnetic-field-induced superconductivity predicted in Kondo-impurity systems.

Application of model to proximity systems clarifies long-standing puzzles.

Abstract

Reentrant behavior is known to exist and magnetic-field-induced superconductivity has been predicted in superconductors with Kondo impurities. We present a simple framework for understanding these phenomena and generalize it to explain the long-standing puzzle of paramagnetic reentrance in thick proximity systems as due to small amounts of Kondo impurities.