Characterization of suitable buffer layers on Cu and Cu–alloy metal substrates for the development of coated conductors

Power applications of high-temperature superconducting (HTS) coated conductors will require stabilization against thermal runaway. We have developed conductive buffer layers to electrically couple the HTS layer to the underlying metal substrate. The structure comprises the layer sequence of SrRuO3 (SRO) on LaNiO3 (LNO) on biaxially textured Ni substrates. We report baseline investigations of compatibility of SRO/LNO multilayer structure with processing of Yba2Cu3O7−δ (YBCO) and demonstrate biaxially textured YBCO films on conductively buffered Ni tapes. These YBCO coatings exhibit self-field Jc values as high as 1.3 × 106 A/cm2 at 77 K, and the entire structure (HTS + conductive buffers + metal substrate) shows good electrical connectivity. These results demonstrate that SRO/LNO buffer layers may provide a basis for stabilized coated conductors.

Download Full-text

R&D of Coated Conductors in Japan

MRS Proceedings ◽

10.1557/proc-659-ii1.1 ◽

2000 ◽

Vol 659 ◽

Cited By ~ 3

Author(s):

Yuh Shiohara ◽

Toru Izumi

Keyword(s):

Research Group ◽

Liquid Nitrogen Temperature ◽

Film Deposition ◽

Coated Conductors ◽

Buffer Layers ◽

High Magnetic Fields ◽

Metal Substrates ◽

Related Research ◽

Current Densities ◽

Deposition Processes

ABSTRACTThe recent achievements of critical current densities in excess of 1MA/cm2 at 77K in YBCO films deposited over appropriate bi-axially textured buffer layers/metal substrates have stimulated interest in the potential future applications of coated conductors at liquid nitrogen temperature and high magnetic fields, which are called as the next/second generation tape conductors. Several different processes for obtaining the bi-axially textured buffer layers/metal substrates as well as thicker film deposition processes and non-vacuum processes are reviewed. This paper reviews the research goals of the project including the recent development of the related research by individual research group in Japan.

Download Full-text

Stability and Microstructure Characterization of Barrierless Cu (Sn, C) Films

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1052.163 ◽

2014 ◽

Vol 1052 ◽

pp. 163-168 ◽

Cited By ~ 1

Author(s):

Xiao Na Li ◽

Lu Jie Jin ◽

Li Rong Zhao ◽

Chuang Dong

Keyword(s):

Diffusion Barrier ◽

Amorphous Layer ◽

Barrier Effect ◽

Co Doping ◽

Cu Alloy ◽

Large Atom ◽

Cu Film ◽

Small Atom ◽

Lower Resistivity

Thermal stability, adhesion and electronic resistivity of the Cu alloy films with diffusion barrier elements (large atom Sn and small atom C) have been studied. Ternary Cu (0.6 at.% Sn, 2 at.% C) films were prepared by magnetron co-sputtering in this work. The microstructure and resistivity analysis on the films showed that the Cu (0.6 at.% Sn, 2 at.% C) film had better adhesion with the substrate and lower resistivity (2.8 μΩ·cm, after annealing at 600 °C for 1 h). Therefore, the doping of carbon atoms makes less effect to the resistivity by decreasing the amount of the doped large atoms, which results in the decreasing of the whole resistivity of the barrierless structure. After annealing, the doped elements in the film diffused to the interface to form self-passivated amorphous layer, which could further hinder the diffusion between Cu and Si. So thus ternary Cu (0.6 at.% Sn, 2 at.% C) film had better diffusion barrier effect. Co-doping of large atoms and small atoms in the Cu film is a promising way to improve the barrierless structure.

Download Full-text