c-axis electrodynamics of ybco

TL;DR

This paper investigates the c-axis electrodynamics of YBCO, revealing that c-axis transport remains incoherent below Tc and exhibits distinct behavior from the ab-plane, challenging previous assumptions about anisotropic superconductivity.

Contribution

It provides new measurements of surface impedance in YBCO, showing unique c-axis behavior that differs from in-plane properties, highlighting incoherent transport below Tc.

Findings

c-axis penetration depth lacks linear temperature dependence

c-axis microwave conductivity decreases then slightly rises below 20K

c-axis transport remains incoherent below Tc

Abstract

New measurements of surface impedance in ybco show that the c-axis penetration depth and conductivity below Tc exhibit behaviour different from that observed in the planes. The c-axis penetration depth never has the linear temperature dependence seen in the ab-plane. Instead of the conductivity peak seen in the planes, the c-axis microwave conductivity falls to low values in the superconducting state, then rises slightly below 20K. These results show that c-axis transport remains incoherent below Tc, even though this is one of the least anisotropic cuprate superconductors.