Onset of the Meissner effect at 65 K in FeSe thin film grown on Nb doped SrTiO3 substrate

TL;DR

This study demonstrates that FeSe thin films on Nb-doped SrTiO3 exhibit a Meissner effect onset at 65 K, indicating a high superconducting transition temperature among iron-based superconductors, confirmed by mutual inductance measurements.

Contribution

The paper provides direct experimental evidence of a 65 K onset of superconductivity in FeSe thin films on Nb-doped SrTiO3, the highest among iron-based superconductors, using mutual inductance techniques.

Findings

Onset of diamagnetic screening at 65 K

Superconducting transition broadens under magnetic field

FeSe thin film has the highest TC among iron-based superconductors

Abstract

We report the Meissner effect studies on an FeSe thin film grown on Nb doped SrTiO3 substrate by molecular beam epitaxy. Two-coil mutual inductance measurement clearly demonstrates the onset of diamagnetic screening at 65 K, which is consistent with the gap opening temperature determined by previous angle resolved photoemission spectroscopy results. The applied magnetic field causes a broadening of the superconducting transition near the onset temperature, which is the typical behavior for quasi-two-dimensional superconductors. Our results provide direct evidence that FeSe thin film grown on Nb doped SrTiO3 substrate has an onset TC ~ 65 K, which is the highest among all iron based superconductors discovered so far.