Effect of Pt doping on the critical temperature and upper critical field in YNi2-xPtxB2C (x=0-0.2)

TL;DR

This study explores how Pt doping affects the superconducting critical temperature and upper critical field in YNi2-xPtxB2C, revealing unconventional behavior linked to increased intraband scattering in a multiband superconductor.

Contribution

It provides new insights into the effects of non-magnetic impurity doping on the superconducting properties of YNi2B2C, especially regarding the upper critical field behavior.

Findings

Critical temperature decreases with Pt doping.

Upper critical field decreases with doping, contrary to conventional expectations.

Density of states and Debye temperature remain constant.

Abstract

We investigate the evolution of superconducting properties by doping non-magnetic impurity in single crystals of YNi2-xPtxB2C (x=0-0.2). With increasing Pt doping the critical temperature (Tc) monotonically decreases from 15.85K and saturates to a value ~13K for x>0.14. However, unlike conventional s-wave superconductors, the upper critical field (HC2) along both crystallographic directions a and c decreases with increasing Pt doping. Specific heat measurements show that the density of states (N(EF)) at the Fermi level (EF) and the Debye temperatures (Theta_D) in this series remains constant within the error bars of our measurement. We explain our results based on the increase in intraband scattering in the multiband superconductor YNi2B2C.