Superconductivity controlled bulk magnetism

TL;DR

This paper demonstrates the coexistence of superconductivity and bulk magnetism in a superconducting spin valve system, revealing controllable micro-magnetic states that impact superconducting properties, with potential applications in cryogenic in-memory computing.

Contribution

It provides experimental evidence of coexistence and control of superconductivity and magnetism, introducing a new approach for cryogenic memory devices.

Findings

Reproducible zero field micro-magnetic states depend on superconducting strength.

Superconducting exchange coupling enables bistable magnetic states.

Multiple resistance states are achieved through magnetic and superconducting interactions.

Abstract

Ferromagnetism's ability to influence superconducting order is well known and well established, but the converse phenomena remains relatively less explored. Theoretical work on the subject includes Anderson and Suhl prediction of a crypto-ferromagnetic state, and De Gennes proposal of two ferromagnetic insulators exchange coupled through a superconductor. In this study, we present compelling evidence of coexistence of both phenomena in a superconducting spin valve system. We demonstrate that superconducting exchange coupling enables reliable bistable states, and the coexistence of SEC and CFM leads to a wide range of reproducible zero field micro-magnetic states in the SSV, which are a function of the strength of the superconducting state. These micromagnetic states can in turn influence the superconducting state, leading to multiple reproducible and non-volatile resistance states; thus paving the way for a novel direction in cryogenic in-memory computing.