# High-resistance YBa2Cu3O7-x grain-boundary Josephson junctions fabricated by electromigration

## TL;DR

This paper introduces a novel oxygen electromigration method to modify the barrier properties of high-Tc YBCO grain-boundary Josephson junctions, increasing their resistance while maintaining their quantum characteristics, enabling better quantum phenomena studies.

## Contribution

It presents a new approach using oxygen electromigration to control the resistance of YBCO junctions without degrading their performance.

## Key findings

- Resistance increased from tens to hundreds of Ohms.
- Barrier height and thickness were quantitatively determined.
- Characteristic voltage IcRn remained unchanged.

## Abstract

[100]-tilt grain-boundary YBa2Cu3O7-x (YBCO) junctions are promising for investigation of macroscopic quantum phenomena in high-Tc Josephson junctions. However, fabrication of the [100]-tilt grain-boundary YBCO junctions with a high resistance, which are required to study quantum effects, is difficult because of a high transparency of a tunnel barrier in this type of junctions. Here, we demonstrate a modification of grain-boundary barrier properties with a new approach to an oxygen electromigration in the YBCO grain-boundary junctions when the oxygen diffuses under an applied electric field from the grain-boundary to a BaTbO3 layer deposited atop of an YBCO film. Using this approach, we changed the normal-state resistance of the junctions from tens to several hundred Ohms without a degradation of their characteristic voltage IcRn and determined a barrier height and thickness by measuring the quasiparticle tunnelling current.

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Source: https://tomesphere.com/paper/1908.03784