Cross-over between channeling and pinning at twin boundaries in YBa2Cu3O7 thin films

TL;DR

This study investigates how twin boundaries in YBa2Cu3O7 thin films influence the critical current, revealing a crossover from vortex channeling to pinning regimes depending on temperature and magnetic field conditions.

Contribution

It introduces a quantitative model for flux-cutting-mediated vortex channeling and identifies a crossover to twin boundary pinning effects in YBa2Cu3O7 films.

Findings

Strong suppression of Jc along twin boundaries at certain conditions

Crossover from vortex channeling to planar pinning regimes

Intrinsic pinning along twin boundaries is comparable to inter-twin pinning

Abstract

The critical current (Jc) of highly twinned YBa2Cu3O7 films has been measured as a function of temperature, magnetic field and angle. For much of the parameter space we observe a strong suppression of Jc for fields in the twin boundary (TB) directions; this is quantitatively modeled as flux-cutting-mediated vortex channeling. For certain temperatures and fields a cross-over occurs to a regime in which channeling is blocked and the TBs act as planar pinning centers so that TB pinning enhances the overall Jc. In this regime, intrinsic pinning along the TBs is comparable to that between the twins.