High Critical Current Density 4 MA/cm2 in Co-Doped BaFe2As2 Epitaxial Films Grown on (La, Sr)(Al, Ta)O3 Substrates without Buffer Layers

TL;DR

This study reports the achievement of high critical current density in Co-doped BaFe2As2 epitaxial films grown directly on specific substrates, demonstrating improved superconducting properties comparable to single crystals.

Contribution

The paper demonstrates the successful growth of high-quality Co-doped BaFe2As2 films with record critical current density on (La, Sr)(Al, Ta)O3 substrates without buffer layers.

Findings

Critical current density of 4 MA/cm2 at 4 K achieved

Films showed high crystallinity and minimal impurities

Superconducting transition width of 1.1 K

Abstract

High critical current densities Jc of 4 MA/cm2 at 4 K were obtained in Co-doped BaFe2As2 (BaFe2As2:Co) epitaxial films grown directly on (La, Sr)(Al, Ta)O3 substrates by pulsed laser deposition. Use of a highly pure target and improvement of film homogeneity were the critical factors to achieve the high Jc. The improved BaFe2As2:Co epitaxial films contained almost no Fe impurity and showed high crystallinity (crystallite tilt angle delta omega = 0.5 deg and twist angle delta fai = 0.5 deg) and a sharp superconducting transition with a width of 1.1 K. It is considered that these improvements resulted in the enhanced superconducting properties comparable to those of single crystals.