Superconductivity-induced change in magnetic anisotropy in epitaxial ferromagnet-superconductor hybrids with spin-orbit interaction

TL;DR

This paper demonstrates how superconductivity can alter the magnetic anisotropy of a ferromagnetic layer via spin-orbit coupling, enabling new ways to control magnetic properties in cryogenic devices.

Contribution

It reveals a novel mechanism where superconductivity influences magnetic anisotropy through triplet Cooper pairs and spin-orbit interaction in heterostructures.

Findings

Superconductivity modifies the magnetocrystalline anisotropy of Fe layers.

Triplet Cooper pairs contribute to free energy changes affecting magnetization.

Magnetic anisotropy can be tuned using superconducting states in heterostructures.

Abstract

The interaction between superconductivity and ferromagnetism in thin film superconductor/ferromagnet heterostructures is usually reflected by a change in superconductivity of the S layer set by the magnetic state of the F layers. Here we report the converse effect: transformation of the magnetocrystalline anisotropy of a single Fe(001) layer, and thus its preferred magnetization orientation, driven by the superconductivity of an underlying V layer through a spin-orbit coupled MgO interface. We attribute this to an additional contribution to the free energy of the ferromagnet arising from the controlled generation of triplet Cooper pairs, which depends on the relative angle between the exchange field of the ferromagnet and the spin-orbit field. This is fundamentally different from the commonly observed magnetic domain modification by Meissner screening or domain wall-vortex interaction and offers the ability to fundamentally tune magnetic anisotropies using superconductivity - a key step in designing future cryogenic magnetic memories.