Development of all chemical solution derived Ce_0.9La_0.1O_{2 −y}/Gd₂Zr₂O₇buffer layer stack for coated conductors: influence of the post-annealing process on surface crystallinity

Abstract

Preparation and characterization of a biaxially textured Gd 2 Zr 2 O 7 and Ce 0.9 La 0.1 O 2−y (CLO, cap)/Gd 2 Zr 2 O 7 (GZO, barrier) buffer layer stack by the metal-organic deposition route are reported. YBa 2 Cu 3 O 7−d (YBCO) superconductor films were deposited by the pulsed-laser deposition (PLD) technique to assess the efficiency of such a novel buffer layer stack. Biaxial texture quality and morphology of the buffer layers and the YBCO superconductor films were fully characterized. The surface crystallinity of the buffer layers is studied by the electron backscatter diffraction technique. It is revealed that post-annealing GZO films in 2% H 2 in Ar is an effective way to improve the surface crystallinity. As a result, a highly textured CLO film can grow directly on the GZO film at a lower crystallization temperature. The critical current density of a YBCO PLD film is higher than 1 MA cm −2 (@77 K, in self-field), demonstrating that the novel CLO/GZO stack is very promising for further development of low cost buffer layer architectures for coated conductors.

Influence of interface reactions on the YBCO films grown by fluorine-free solution route

“…The CLO films and the YBCO-Ag films deposited by chemical solution routes were published previously [1,3]. Briefly, the CLO films were prepared by using a propionatesbased metal-organic solution, while the YBCO-Ag films were prepared by a novel sliver-assist fluorine-free MOD solution route.…”

“…In our previous study, we proposed and developed La doped CeO 2 (Ce 0.9 La 0.1 O 2-y , CLO) as a cap layer for an all-chemical derived coated conductors' configuration [1]. An YBCO layer prepared from low-fluorine MOD route was grown on a CLO buffered yttrium stabilized ZrO 2 (YSZ) template and exhibited high performance (>3 MA/cm 2 , self-field, 77 K) comparable with that of films grown on single crystalline LaAlO 3 by the similar route [2].…”

Texture evolution of chemically deposited La2Zr2O7 buffer layer for coated conductors

“…Therefore, a buffer layer is crucial to obtain high critical current density (J c ). Various interlayers can act as a barrier against the two main defects mentioned above, and transfer the texture from the substrate up to the YBCO superconducting layer [5][6][7][8][9]. In recent years, chemical solution deposition (CSD) has proven to be more promising route than physical approaches to fabricate long coating lengths.…”

Aqueous Chemical Solution Deposition of Novel, Thick and Dense Lattice-Matched Single Buffer Layers Suitable for YBCO Coated Conductors: Preparation and Characterization

“…Hence, buffer layers are absolutely necessary for coated conductor designs. Many buffer layers, including lanthanum zirconate (LZO) [2,3,4,5,6], cerium oxide (CeO 2 ) [7,8,9,10] and other lattice-matched buffer layers [11,12,13,14,15,16,17,18,19,20] which are prepared basically using solution-based methods have been used. These buffer layers should not only stop diffusion but also transfer the epitaxial texture of Ni-5% W substrate to the superconducting layer.…”

“…Owing to the high cost of multiple buffer layer depositions of LZO and CeO 2 , researchers have focused on preparing a single buffer layer with almost 0% lattice mismatch with YBCO and it was reported that the in-plane orientation of YBCO can be improved with these lattice matched buffer layers [11,12,13,14,15,16,17,18]. …”