MOD derived pyrochlore films as buffer layer for all-chemical YBCO coated conductors

TL;DR

This study demonstrates the successful use of MOD-derived La2Zr2O7 pyrochlore films as buffer layers for YBCO coated conductors, achieving high-quality epitaxial films and excellent superconducting properties.

Contribution

It introduces a novel application of MOD-grown La2Zr2O7 pyrochlore films as effective buffer layers for YBCO conductors, with optimized processes for high performance.

Findings

YBCO films with Tc above 90 K on buffer layers

Critical current density Jc > 1 MA/cm2 at 77 K

High irreversibility field of 8.3 T at 77 K

Abstract

We report a detailed study performed on La2Zr2O7 (LZO) pyrochlore material grown by Metal-Organic Decomposition (MOD) method as buffer layers for YBa2Cu3O7-x (YBCO) coated conductors. High quality epitaxial LZO thin films have been obtained on single crystal (SC) and Ni-5%at.W substrates. In order to evaluate structural and morphological properties, films have been characterized by means of X-ray diffraction analyses (XRD), atomic force microscope (AFM) and scanning electron microscope (SEM). Precursors solutions and heat treatments have been studied by thermogravimetric analyses (TG-DTA-DTG) and infrared spectra (FT-IR) with the aim of optimizing the annealing process. Thin films of YBCO have been deposited by pulsed laser ablation (PLD) on this buffer layers. The best results obtained on SC showed YBCO films with critical temperature values above 90 K, high self field critical current density values (Jc > 1 MA/cm2) and high irreversibility field values (8.3 T) at 77 K together with a rather high depinning frequency vp (0.5 T, 77 K)>44 GHz as determined at microwaves. The best results on Ni-5%at.W has been obtained introducing in the heat treatment a pyrolysis process at low temperature in air in order to remove the residual organic part of the precursor solution.