Attractive interaction between superconducting vortices in tilted magnetic fields

Alexandre Correa,Federico Mompeán,Takanari Kashiwagi,Alexander I Buzdin,Takashi Yamamoto,Carmen Munuera,Isabel Guillamón,Edwin Herrera,Hermann Suderow,Mar García-Hernández,Kazuo Kadowaki

doi:10.1038/s42005-019-0132-x

Abstract

Many practical applications of high Tc superconductors involve layered materials and magnetic fields applied on an arbitrary direction with respect to the layers. When the anisotropy is very large, Cooper pair currents can circulate either within or perpendicular to the layers. Thus, tilted magnetic fields lead to intertwined lattices of Josephson and Abrikosov vortices, with quantized circulation across and within layers, respectively. Transport in such intertwined lattices has been studied in detail, but direct observation and manipulation of vortices remains challenging. Here we present magnetic force microscopy experiments in tilted magnetic fields in the extremely quasi-two dimensional superconductor Bi2Sr2CaCu2O8. We trigger Abrikosov vortex motion in between Josephson vortices, and find that Josephson vortices in different layers can be brought on top of each other. Our measurements suggest that intertwined lattices in tilted magnetic fields can be intrinsically easy to manipulate thanks to the mutual interaction between Abrikosov and Josephson vortices.

Highlights

Many practical applications of high Tc superconductors involve layered materials and magnetic fields applied on an arbitrary direction with respect to the layers
Buzdin et al.[4] showed that the pancake vortices in such composite vortex lattices in tilted magnetic fields attract each other at large distances when located on top of a Josephson vortex
Most previous experiments dealing with crossing Josephson and pancake vortex lattices were made close to liquid nitrogen temperatures using non-invasive imaging such as scanning Hall microscopy

Summary

Introduction

Many practical applications of high Tc superconductors involve layered materials and magnetic fields applied on an arbitrary direction with respect to the layers. Tilted magnetic fields lead to intertwined lattices of Josephson and Abrikosov vortices, with quantized circulation across and within layers, respectively. The mutual interaction between the columns of pancake vortices and the Josephson vortices leads to deformed combined lattices consisting of tilted vortex lines having kinks and different arrangements composed by layers with alternating pancake and Josephson vortices[2,3]. Pancake vortices are not exactly on top of each other, as usual in an Abrikosov lattice in perpendicular fields, but are slightly displaced along the length of the Josephson vortex This is due to the Lorentz force from the intralayer currents, which are directed opposite to each other in each layer. There is a phase change of 2π across each vortex, once across layers for a Josephson vortex and once within each layer for a pancake vortex

Methods

Results

Conclusion