Exceptional Suppression of Flux-Flow Resistivity in FeSe${}_{0.4}$Te${}_{0.6}$ by Back-Flow from Excess Fe Atoms and Se/Te Substitutions

Tatsunori Okada, Fuyuki Nabeshima, Hideyuki Takahashi +2

We measured the microwave surface impedance of FeSe${}_{0.4}$Te${}_{0.6}$ single crystals with- and without external magnetic fields. The superfluid density exhibited a quadratic tempe…