Low field vortex matter in YBCO: an atomic beam magnetic resonance study

TL;DR

This study uses a novel atomic beam magnetic resonance technique to investigate the low field vortex lattice structure in untwinned YBCO, revealing a weakly distorted triangular lattice and measuring key superconducting parameters.

Contribution

It introduces and applies the first detailed atomic beam magnetic resonance method to study vortex matter in YBCO, providing new insights into vortex lattice structure and superconductor properties.

Findings

Triangular vortex lattice with orientational order across the sample

Distortion factor of the lattice f=1.16 due to anisotropy

Measured penetration depth lambda_ab=140±20 nm

Abstract

We report measurements of the low field structure of the magnetic vortex lattice in an untwinned YBCO single-crystal platelet. Measurements were carried out using a novel atomic beam magnetic resonance (ABMR) technique. For a 10.7 G field applied parallel to the c-axis of the sample, we find a triangular lattice with orientational order extending across the entire sample. We find the triangular lattice to be weakly distorted by the a-b anisotropy of the material and measure a distortion factor, f = 1.16. Model-experiment comparisons determine a penetration depth, lambda_ab = 140 (+-20) nm. The paper includes the first detailed description of the ABMR technique. We discuss both technical details of the experiment and the modeling used to interpret the measurements.