Precursor superconducting diamagnetism in YBa2Cu3O7-d with in-plane or intercalated magnetic impurities

TL;DR

This study investigates how magnetic impurities in YBa2Cu3O7-d affect precursor diamagnetism above Tc, revealing it remains largely unchanged despite variations in transition temperature, contrasting with behavior in conventional superconductors.

Contribution

It demonstrates that precursor diamagnetism in YBa2Cu3O7-d is insensitive to magnetic impurities, unlike in conventional BCS superconductors, highlighting differences in underlying mechanisms.

Findings

Precursor diamagnetism above Tc is unaffected by magnetic impurities in YBa2Cu3O7-d.

Magnetic impurities significantly alter Tc but not precursor diamagnetism.

Contrasts with conventional superconductors where impurities enhance precursor diamagnetism.

Abstract

The magnetization around the superconducting transition was measured in YBa2Cu3O7-d with magnetic impurities in the CuO2 layers (Cu substituted by Zn or Ni) or between them (Y substituted by Gd or Pr). While some of these impurities have an important effect on the superconducting transition temperature (Tc), the precursor diamagnetism observed above Tc is not appreciably affected. This result contrasts with recent observations in a conventional BCS superconductor (La), in which the precursor diamagnetism was found to increase several orders of magnitude with the addition of a small amount (a few atomic percent) of Gd or Pr magnetic impurities.