Measurement of Conduction Electron Polarization Via the Pairing Resonance

TL;DR

This paper demonstrates that the pairing resonance in ultra-thin superconducting aluminum films can serve as a spin-resolved probe to measure conduction electron polarization in thin magnetic films, extending the field range of such measurements.

Contribution

It introduces a novel method using the pairing resonance in superconductors to measure electron polarization in magnetic materials at high magnetic fields.

Findings

Pairing resonance can be used as a spin probe in superconducting films.

The technique extends the measurable magnetic field range beyond previous limits.

Limitations of the method are discussed.

Abstract

We show that the pairing resonance in the Pauli-limited normal state of ultra-thin superconducting Al films provides a spin-resolved probe of conduction electron polarization in thin magnetic films. A superconductor-insulator-ferromagnet tunneling junction is used to measure the density of states in supercritical parallel magnetic fields that are well beyond the Clogston-Chandresekhar limit, thus greatly extending the field range of the tunneling density of states technique. The applicability and limitations of using the pairing resonance as a spin probe are discussed.