Veerle Cloet

A water-based sol–gel technique for chemical solution deposition of (RE)Ba2Cu3O7−y (RE = Nd and Y) superconducting thin films

The achievement of low-cost deposition techniques for high critical current (RE)Ba2Cu3O7?y-coated conductors is one of the major objectives in achieving a widespread use of superconductivity in power applications. Chemical solution deposition techniques are appearing as a very promising methodology to achieve highly textured oxide thin films at a low cost, so an intense effort is being carried out to develop routes for all chemically coated conductor tapes. In this work recent achievements will be presented towards the goal of the development of an environmentally friendly, completely water-based sol?gel technique for the deposition of thin superconducting films on SrTiO3 single-crystal substrates using the dip coat technique. A comparison is made between aqueous sol?gel synthesis of two (RE)Ba2Cu3O7?y superconducting systems: YBa2Cu3O7?y and its homologue NdBa2Cu3O7?y. Our conclusions are that YBa2Cu3O7?y still remains the material of choice for coated conductor development using this sol?gel technique, with a Tc,onset of 91?K and Jc of 0.3?MA?cm?2.

Sol-Gel Ink-Jet Printing Technique for Synthesis of Buffer Layers of Coated Conductors

In this present work, two buffer layers (La2Zr2O7 and CeO2) were deposited by a non-contact computer-controlled ink-jet coating technique with sol-gel precursors on highly textured Ni-5%W Rolling Assisted Biaxially Textured substrates (RABiTS). Lanthanum acetate and cerium acetylacetonate were used as precursors for the LZO and CeO2 sol respectively. After a high temperature heat treatment (heating at 900°C for LZO and at 1100°C for CeO2) under reducing atmosphere, epitaxial textured buffer layers were obtained. XRD and pole figures were used to analyse the texture of the films, the microstructure was analysed by SEM.

A Water-Based Sol-Gel Precursor for Deposition of Thin La2Zr2O7 Layers on Ni-W Substrates

Through dip-coating Ni-5%W substrates in a water-based sol-gel solution, thin films of La₂Zr₂O₇ (LZO) were produced. This method yields highly crystalline and epitaxial films. The surface of the LZO film was found to be smooth and homogeneous. Subsequently, CeO₂ layers followed by an YBa₂Cu₃O_7-y layer were deposited via Pulsed Laser Deposition (PLD) onto the LZO film. The crystallinity and biaxial texture of the LZO layer was successfully transferred to the next layers, as demonstrated by pole figures and RHEED measurements. Resistive T_c-measurements were carried out on these samples and showed a T_c of 85 K.

A Water-Based Sol-Gel Precursor for Deposition of Thin Layers on Ni-W Substrates

Through dip-coating Ni-5%W substrates in a water-based sol-gel solution, thin films of La₂Zr₂O₇ (LZO) were produced. This method yields highly crystalline and epitaxial films. The surface of the LZO film was found to be smooth and homogeneous. Subsequently, CeO₂ layers followed by an YBa₂Cu₃O_7-y layer were deposited via Pulsed Laser Deposition (PLD) onto the LZO film. The crystallinity and biaxial texture of the LZO layer was successfully transferred to the next layers, as demonstrated by pole figures and RHEED measurements. Resistive T_c-measurements were carried out on these samples and showed a T_c of 85 K.

A Water-Based Sol-Gel Precursor for Deposition of Thin

Through dip-coating Ni-5%W substrates in a water-based sol-gel solution, thin films of La₂Zr₂O₇ (LZO) were produced. This method yields highly crystalline and epitaxial films. The surface of the LZO film was found to be smooth and homogeneous. Subsequently, CeO₂ layers followed by an YBa₂Cu₃O_7-y layer were deposited via Pulsed Laser Deposition (PLD) onto the LZO film. The crystallinity and biaxial texture of the LZO layer was successfully transferred to the next layers, as demonstrated by pole figures and RHEED measurements. Resistive T_c-measurements were carried out on these samples and showed a T_c of 85 K.

{\rm La}_{2}{\rm Zr}_{2}{\rm O}_{7}

In general, the sol-gel method is a very attractive route for ceramic synthesis because it permits direct fabrication of multi-component ceramics in different configurations without powder intermediates. This diversity, in which materials can be formed, has made the sol-gel method an important synthesis route in several domains of research. For (RE)Ba2Cu3O7-y superconducting thin film development, chemical solution deposition (CSD) techniques starting from sol-gel precursors can offer a cost-effective and more flexible large-scale alternative synthesis route in comparison to the common used vacuum techniques. This work describes the deposition of thin NdBa2Cu3O7-y layers on SrTiO3 single crystals based on a new sol-gel dip coating process using aqueous precursor solutions. Two inorganic aqueous sol-gel routes were investigated, a metal nitrate - citric acid based and a metal acetate - triethanol amine based solution.