Anisotropic spin-current spectroscopy of ferromagnetic superconducting gap symmetries

TL;DR

This paper presents a microscopic theory for tunneling spin transport at ferromagnetic insulator-superconductor interfaces, enabling the probing of superconducting gap symmetries via spin currents influenced by ferromagnetic resonance.

Contribution

It introduces a method to extract spin susceptibilities and gap symmetries of ferromagnetic superconductors through spin current measurements, advancing spintronic applications.

Findings

Spin susceptibilities can be deduced from spin currents.

Tuning the FSC easy axis reveals superconducting gap symmetries.

The approach links magnetism and superconductivity for spin device development.

Abstract

We develop a microscopic theory of tunneling spin transport at the magnetic interface between a ferromagnetic insulator and a ferromagnetic superconductor (FSC) driven by ferromagnetic resonance. We show that the spin susceptibilities of the FSC can be extracted from the spin currents by tuning the easy axis of the FSC, and thus the spin currents can be a probe for the symmetries of the spin-triplet Cooper pairing. Our results will offer a route to exploiting the synergy of magnetism and superconductivities for spin devices.