Effects of the CuO chains on the anisotropic penertration depth of YBa2Cu4O8

TL;DR

This study investigates how CuO chains influence the anisotropic magnetic penetration depth in YBa2Cu4O8, revealing a sqrt(T) dependence suggesting a specific low-energy density of states, with implications for layered superconductor models.

Contribution

It provides new experimental data on the temperature dependence of penetration depth along different crystal axes and discusses the effects of CuO chains within a proximity model.

Findings

Both λ_ab and λ_c vary as √T up to 0.4Tc.

Results support a proximity model with alternating superconducting and normal layers.

The data imply a square root density of states at low energy.

Abstract

The temperatuer dependence of the magnetic penetration depth of grain aligned YBa2Cu4O8 has been measured along the ab plane and c-axis. Both $\lambda_ab$ and $\lambda_c$ vary as \sqrt{T} up to 0.4Tc implying a square root density of states at low energy. The results are discussed in terms of a proximity model of alternating stacked superconducting and normal layers