Suppression of Superconductivity in UPt_3 Single Crystals

TL;DR

This study investigates how defects and annealing affect the superconducting transition temperature in high-quality UPt_3 single crystals, revealing an intrinsic Tc of about 563 mK and the suppression mechanisms involved.

Contribution

It demonstrates the systematic variation of Tc through annealing and models defect-induced suppression using a modified Abrikosov-Gor'kov formula considering anisotropic effects.

Findings

Intrinsic Tc of UPt_3 is approximately 563 mK.

Superconductivity suppression aligns with a modified Abrikosov-Gor'kov model.

Annealing can systematically tune the superconducting transition temperature.

Abstract

High quality single crystals of UPt_3 have been prepared by vertical float-zone refining in ultra-high vacuum. We find that the superconducting transition temperature can be varied systematically by annealing, revealing that the transition temperature intrinsic to UPt_3 is 563 +/- 5 mK. The suppression of the superconducting transition from defects is consistent with a modified Abrikosov-Gor'kov formula that includes anisotropic pairing, Fermi surface anisotropy, and anisotropic scattering by defects.