Intrinsic magnetization of the superconducting condensate in Fe(Te,Se)

TL;DR

This paper provides experimental evidence of intrinsic spin-polarized magnetization in the superconducting condensate of Fe(Te,Se), revealing novel magnetic phenomena and potential for superconducting spintronics.

Contribution

It demonstrates the existence of an intrinsic magnetic field in Fe(Te,Se) superconductors and introduces a minimal Rashba-based model to explain the observations.

Findings

Intrinsic magnetic field scales linearly with DC bias current.

Magnetoresistance shows dual flux-quantization effects.

Evidence for spin-polarized superconductivity at the device scale.

Abstract

A spin-polarized superconducting condensate generates a net magnetization with measurable signatures. We present evidence for an intrinsic magnetic field in mesoscopic Fe(Te,Se) rings. The intrinsic field, encoded in the phase of superconducting quantum oscillations, scales linearly with the DC bias current, and its orientation exhibits an anomalous dependence on polarity and magnitude of the applied current. The magnetoresistance displays a dual flux-quantization effect with respect to the external magnetic field and the DC current. A minimal model incorporating Rashba coupling with an effective anisotropic out-of-plane interaction accounts for the experimental observations. These results provide evidence for spin-polarized superconductivity at the device scale and open new opportunities for superconducting spintronic and quantum information platforms.