Order-disorder transition induced by deformation of vortex lines at the twin boundaries in YBa$_2$Cu$_3$O$_{7-\delta}$-crystals: test of the Lindemann criteria

TL;DR

This paper demonstrates that tilting the magnetic field in YBa2Cu3O7-δ crystals causes an order-disorder transition in vortex matter, driven by vortex line deformations near twin boundaries that follow Lindemann criteria, affecting vortex dynamics.

Contribution

It provides experimental evidence linking vortex line deformations at twin boundaries to the Lindemann criterion, explaining the order-disorder transition in vortex phases.

Findings

Transition from ordered to disordered vortex phase with field tilt.

Increase in depinning current during transition.

Change from elastic to plastic vortex creep.

Abstract

We show that rotation of the magnetic field off the plane of twin boundaries (TB's) induces transition of an ordered vortex solid phase to a disordered one. This transition arises due to appearance of transverse deformations of vortex lines near the TB's, $u_{t,TB}$, the amplitude of which satisfies the Lindemann criteria, $u_{t,rp}=c_La_0$. This order-disorder transition is accompanied by an increase in the depinning current, by crossover from an elastic creep to plastic one, and by appearance of the $S$-shaped voltage-current characteristics.