Superconducting exchange coupling driven bistable and absolute switching

TL;DR

This paper demonstrates a superconducting device that exhibits bistable resistance states driven by exchange coupling between ferromagnetic insulators and a superconducting layer, enabling non-volatile cryogenic memory for quantum circuits.

Contribution

It provides experimental evidence of superconducting exchange coupling inducing bistable resistance states, with potential applications in cryogenic memory and superconducting spintronics.

Findings

Exchange coupling promotes switching between resistance states.

Devices exhibit zero and finite resistance states at zero magnetic field.

Demonstrates absolute switching for cryogenic memory applications.

Abstract

As per de Gennes predictions, a superconducting layer placed between two ferromagnetic insulators can drive an antiferromagnetic exchange coupling between them. Using two ferromagneticinsulating GdN layers having dissimilar switching fields sandwiching a superconducting Vanadium thin film, we demonstrate evidence of such exchange coupling. We demonstrate that such an exchange coupling promotes switching between zero and finite resistance states of Vanadium. Our devices hold either a finite resistance or a zero-resistance state at zero magnetic field, dependent on their magnetic field history. Moreover, we demonstrate the absolute switching effect, thus making such devices suitable for application at the lowest temperatures as non-volatile cryogenic memory useful for futuristic quantum circuits and for several other superconducting spintronic applications.