Direct observation of quantized interlayer vortex flow and vortex pinning distribution in high-Tc La_(1.87)Sr_(0.13)CuO_4 single crystals

TL;DR

This study uses a SQUID microscope to directly observe quantized interlayer vortex motion and pinning in high-Tc LaSrCuO4 crystals, revealing current-dependent flux modes and inhomogeneous pinning distributions.

Contribution

It provides the first direct imaging of vortex flow modes and pinning distribution in high-Tc superconductors under varying currents.

Findings

Identification of three flux motion modes depending on current

Transition from vortex creep to steady flow with increasing current

Inhomogeneous vortex-flow area expansion indicating varied pinning centers

Abstract

A scanning superconducting quantum interference device (SQUID) microscope (SSM) is used to study the magnetic imaging of dynamic motion of quantized interlayer vortices induced by the Lorentz force in anisotropic high-Tc La_(1.87)Sr_(0.13)CuO_4 single crystals. It is found that 3 modes of flux motion switch depending on the transport current. By increasing the current a transition from the creep-like behavior of vortices to a steady flow of vortices was observed. Even higher current induced a continuous expansion of vortex-flow area indicating an inhomogeneous distribution of various pinning centers.