Anisotropy and directional pinning in YBaCuO with BaZrO3 nanorods

TL;DR

This study investigates how BaZrO3 nanorods influence anisotropic vortex behavior in YBa2Cu3O7-x, revealing that effective-mass scaling applies only to intrinsic properties and that nanorods induce a vortex Mott phase transition.

Contribution

It demonstrates the selective applicability of effective-mass scaling and uncovers a vortex Mott phase transition driven by nanorods in YBa2Cu3O7-x.

Findings

Effective-mass angular scaling applies only to flux-flow resistivity.

Nanorods induce a transition toward a vortex Mott phase.

Strong pinning partly results from dynamic effects.

Abstract

Measurements of anisotropic transport properties (dc and high-frequency regime) of driven vortex matter in YBa$_2$Cu$_3$O$_{7-x}$ with elongated strong-pinning sites (c-axis aligned, self-assembled BaZrO$_3$ nanorods) are used to demonstrate that the effective-mass angular scaling takes place only in intrinsic physical quantities (flux-flow resistivity), and not in pinning-related Labusch parameter and critical currents. Comparison of the dynamics at different time scales shows evidence for a transition of the vortex matter toward a Mott phase, driven by the presence of nanorods. The strong pinning in dc arises partially from a dynamic effect.