Development of a Fluorine-Free Polymer-Assisted-Deposition Route for YBa2Cu3O7−x Superconducting Films

Mircea Nasui,Cornelia Pop,Ramona Bianca Sonher,Sorin Varodi,Lelia Ciontea,Traian Petrisor

doi:10.3390/coatings10100966

Abstract

Polymer assisted deposition (PAD) was used as an environmentally friendly, non-fluorine, growth method for superconducting YBa2Cu3O7−x (YBCO) films. The kinetics of the thermal decomposition of the precursor powder was studied by thermogravimetry coupled with mass spectrometry (TG-QMS). YBCO films were spin coated on (100) SrTiO3 (STO) single crystalline substrates, followed by a single step thermal treatment under wet and dry O2 and O2/N2 mixture. The as-obtained films were epitaxially grown having a [001]YBCO||[001]STO out-of-plane epitaxial relationship and exhibited good superconducting properties with Tc (R = 0) > 88 K, transition widths, ΔT ≈ 2 K and critical current densities as high as 2.3 MA/cm2 at 77 K and self magnetic field.

Highlights

High-temperature superconducting (HTS) YBa2 Cu3 O7−x (YBCO) films have been extensively studied mainly due to their potential applications in superconducting electric power applications such as electrical energy transportation, motors, generators, magnets for nuclear fusion, magnetic energy storage, etc. [1]
Chemical solution deposition (CSD) route has proven to be a valid alternative in the formation of complex oxide thin films, that can be scaled-up for long length superconducting tape fabrication [2,3]
The most important aspect of the Polymer assisted deposition (PAD) process is the thermal decomposition of the polymer

Summary

Introduction

High-temperature superconducting (HTS) YBa2 Cu3 O7−x (YBCO) films have been extensively studied mainly due to their potential applications in superconducting electric power applications such as electrical energy transportation, motors, generators, magnets for nuclear fusion, magnetic energy storage, etc. [1]. The CSD of YBCO films involves four steps: precursor synthesis, deposition, decomposition of organic precursors (pyrolysis) and film crystallization. Continuous efforts are being carried out in the development of low-fluorine (see for example [6,7]) and fluorine-free chemical solution deposition processes [8,9,10,11,12]. These approaches consist of dissolving carboxylates, such as acetates, propionates, etc., or β-diketonates, as metal precursors in a common solvent, usually organic acids, and combining the solutions to yield the desired stoichiometry. The combination of short chain carboxylates, such as acetates, and strongly chelating β-diketonates, or propionates of all the metals dissolved in propionic

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