Drastic improvement of surface structure and current-carrying ability in YBa2Cu3O7 films by introducing multilayered structure

TL;DR

Introducing multilayered structures with NdBCO layers significantly enhances the surface smoothness and critical current density of thick YBa2Cu3O7 films, surpassing the performance of thinner films and reducing surface defects.

Contribution

This study demonstrates a novel multilayered approach to improve the surface quality and superconducting properties of thick YBCO films, which was not achieved in previous single-layer films.

Findings

Surface roughness nearly eliminated in multilayers

Critical current density increased by over 3 times in multilayers

Multilayered structures outperform thinner YBCO films in Jc

Abstract

Much smoother surfaces and significantly improved superconducting properties of relatively thick YBa2Cu3O7 (YBCO) films have been achieved by introducing a multilayered structure with alternating main YBCO and additional NdBCO layers. The surface of thick (1 microm) multilayers has almost no holes compared to YBCO films. Critical current density (Jc) have been drastically increased up to a factor > 3 in 1 microm multilayered structures compared to YBCO films over entire temperature and applied magnetic filed range. Moreover, Jc values measured in thick multilayers are even larger than in much thinner YBCO films. The Jc and surface improvement have been analysed and attributed to growth conditions and corresponding structural peculiarities.