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

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.