Transverse and secondary voltages in BSCCO single crystals

TL;DR

This study uses multiterminal electrical transport measurements on BSCCO single crystals to investigate vortex dynamics, revealing a thermally activated vortex loop unbinding process and a coupled 3D/2D phase transition in vortex dimensionality and superconductivity.

Contribution

It demonstrates the existence of guided vortex motion and secondary voltages induced by vortex loop unbinding in BSCCO crystals, highlighting a length-scale-dependent vortex decoupling process.

Findings

Guided vortex motion observed near transition temperature.

Secondary voltage caused by thermally activated vortex loops.

Simultaneous 3D/2D phase transition in vortex and superconducting states.

Abstract

Multicontact configuration is one of the most powerful arrangements for electrical transport measurements applied to study vortex phase transition and vortex phase dimensionality in strongly anisotropic high-Tc superconducting materials. In this paper we present electrical transport measurements using a multiterminal configuration, which prove both the existence of guided vortex motion in BSCCO single crystals near the transition temperature and that secondary voltage in zero external magnetic field is induced by thermally activated vortex loop unbinding. The phase transition between the bound and unbound states of the vortex loops was found to be below the temperature where the phase coherence of the superconducting order parameter extends over the whole volume of the sample. We show experimentally that 3D/2D phase transition in vortex dimensionality is a length-scale-dependent layer decoupling process and takes place simultaneously with the 3D/2D phase transition in superconductivity at the same temperature.