Remotely induced magnetism in a normal metal using a superconducting spin-valve

TL;DR

This paper demonstrates that a superconducting spin-valve can remotely induce magnetization in a non-magnetic metal layer, revealing new possibilities for superconducting spintronics and quantum interference devices.

Contribution

It reports the first observation of remote magnetization in gold induced by a superconducting spin-valve, controlled by temperature and magnetic field.

Findings

Magnetization appears in gold layer separated by Nb superconductor.

Magnetization can be controlled by temperature and magnetic field.

Potential for new quantum interference devices based on Cooper pair spin.

Abstract

Superconducting spintronics has emerged in the last decade as a promising new field that seeks to open a new dimension for nanoelectronics by utilizing the internal spin structure of the superconducting Cooper pair as a new degree of freedom. Its basic building blocks are spin-triplet Cooper pairs with equally aligned spins, which are promoted by proximity of a conventional superconductor to a ferromagnetic material with inhomogeneous macroscopic magnetization. Using low-energy muon spin rotation experiments, we find an entirely unexpected novel effect: the appearance of a magnetization in a thin layer of a non-magnetic metal (gold), separated from a ferromagnetic double layer by a 50 nm thick superconducting layer of Nb. The effect can be controlled by either temperature or by using a magnetic field to control the state of the remote ferromagnetic elements and may act as a basic building block for a new generation of quantum interference devices based on the spin of a Cooper pair.