The Superconductivity, Intragrain Penetration Depth and Meissner Effect of RuSr2(Gd,Ce)2Cu2O10+delta

TL;DR

This study investigates the superconducting properties of RuSr2(Gd,Ce)2Cu2O10+delta, revealing that intragrain superconductivity and the Meissner effect increase significantly despite minimal changes in hole concentration, challenging existing homogeneous cuprate models.

Contribution

The paper presents experimental evidence of phase separation and granularity effects in RuSr2(Gd,Ce)2Cu2O10+delta, contrasting with traditional homogeneous cuprate theories.

Findings

Intragrain Tc varies from 17 to 40 K with minimal p change

Superfluid density and Meissner effect increase over 10 times

Results support phase separation and granularity in the material

Abstract

The hole concentration (p)(delta), the transition temperature Tc, the intragrain penetration depth lambda, and the Meissner effect were measured for annealed RuSr2(Gd,Ce)2Cu2O10+delta samples. The intragrain superconducting transition temperature Tc} varied from 17 to 40 K while the p changed by only 0.03 holes/CuO2. The intragrain superfluid-density 1/lambda^2 and the diamagnetic drop of the field-cooled magnetization across Tc (the Meissner effect), however, increased more than 10 times. All of these findings are in disagreement with both the Tc vs. p and the Tc vs. 1/lambda^2 correlations proposed for homogeneous cuprates, but are in line with a possible phase-separation and the granularity associated with it.