CSD-Grown Y1-xGdxBa2Cu3O7-δ-BaHfO3 Nanocomposite Films on Ni5W and IBAD Technical Substrates.

Pablo Cayado,Bernhard Holzapfel,Jens Hänisch,Hannes Rijckaert,Manuela Erbe,Marco Langer,Alexandra Jung

doi:10.3390/nano10010021

Pablo Cayado, Bernhard Holzapfel + Show 5 more

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https://doi.org/10.3390/nano10010021

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Abstract

Chemical solution deposition (CSD) was used to grow Y1−xGdxBa2Cu3O7−δ-BaHfO3 (YGBCO-BHO) nanocomposite films containing 12 mol% BHO nanoparticles and various amounts of Gd, x, on two kinds of buffered metallic tapes: Ni5W and IBAD. The influence of the rare-earth stoichiometry on structure, morphology and superconducting properties of these films was studied. The growth process was carefully studied in order to find the most appropriate growth conditions for each composition and substrate. This led to a clear improvement in film quality, probably due to the reduction of BaCeO3 formation. In general, the superconducting properties of the films on Ni5W are significantly better. For x > 0.5, epitaxial ~270 nm thick YGBCO-BHO films with Tc > 93 K and self-field Jc at 77 K ~2 MA/cm² were obtained on Ni5W. These results highlight the potential of this approach for the fabrication of high-quality coated conductors.

Highlights

Most of the present-day research in the field of applied superconductivity is devoted to the improvement of second-generation superconducting tapes, so-called coated conductors (CCs) [1,2,3,4], whose base materials are the REBa2Cu3O7−δ (REBCO, RE: rare earth) compounds
The images were takenillubmyinaationn oanpd twiicthaolutmpoilacrrizoatsiocnofiplteers.working in reflection mode with white illumination and without polarizatOionnthfie lotteherrsh. and, the optimal growth conditions for the different YGBCO-BHO films depend on the amount of Gd, x [17]
When using SrTiO3 as a substrate, the optimal crystallization temperature (Tcrys) increases from 780 °C for x = 0 to 810 °C for x = 1 and the optimal oxygen partial pressure reduces from 200 ppm for x = 0 to 50 ppm for x = 1. Those optimized pO2 values have been used with regard to x but, as a consequence of progressing substrate deterioration at high temperatures, the optimal temperatures on metallic tapes had to be adapted, e.g., they decreased to 770 °C for x = 0 and 790 °C for x = 1 (Table 1)

Summary

Introduction

Most of the present-day research in the field of applied superconductivity is devoted to the improvement of second-generation superconducting tapes, so-called coated conductors (CCs) [1,2,3,4], whose base materials are the REBa2Cu3O7−δ (REBCO, RE: rare earth) compounds. A simple possibility to overcome some of the complications in the synthesis of alternative single-RE-BCO compounds but yet to benefit from the improvement of the superconducting properties is to mix different RE3+ ions In this regard, we recently reported on the possibility to enlarge the processing window for epitaxial high-quality films of Y1−xGdxBa2Cu3O7−δ-BaHfO3 (YGBCO-BHO) on single crystal substrates with respect to the corresponding single-RE films [17]. Apart from the benefits of RE mixing, and in order to improve the pinning properties in such films further, secondary phases can be included in the matrix to produce REBCO nanocomposites This topic has been extensively studied by many groups evidencing that the in-field transport properties of REBCO films can be extensively enlarged by using both the “in situ” and the “ex situ” approaches [29,30,31,32,33,34,35,36]. We investigate the influence of morphology, texture quality, and CeO2 buffer layer thickness of these templates on the microstructure and superconducting properties of Y1−xGdxBa2Cu3O7−δ-BaHfO3 nanocomposite films with different Gd content x

Sample Preparation

Thin-Film Characterization

Results and Discussion

Conclusions