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CN-122000130-A - Composite buffer layer structure for high-temperature superconducting tape, preparation method of composite buffer layer structure and superconducting tape

CN122000130ACN 122000130 ACN122000130 ACN 122000130ACN-122000130-A

Abstract

The invention relates to a composite buffer layer structure for a high-temperature superconducting tape, a preparation method thereof and a superconducting tape, and belongs to the technical field of high-temperature superconducting materials. The composite buffer layer structure comprises a first buffer layer and a flattening cap layer formed on the first buffer layer by epitaxial growth of Lanthanum Strontium Manganese Oxide (LSMO) through a pulse laser deposition technology. The invention reduces the interface roughness to the atomic level while maintaining excellent texture quality by introducing the LSMO flattening cap layer, thereby providing a nearly ideal growth template for the superconducting layer. The design effectively solves the problem of quality reduction of the superconducting layer caused by rough surface morphology of the traditional buffer layer, remarkably improves the current carrying performance of the superconducting strip, and is a breakthrough solution for promoting the development of the second-generation high-temperature superconducting technology to higher performance.

Inventors

  • GAO LEI
  • Ying Tianping
  • CHENG JINGUANG

Assignees

  • 中国科学院物理研究所

Dates

Publication Date
20260508
Application Date
20260121

Claims (10)

  1. 1. A composite buffer layer structure for a high temperature superconducting tape, comprising: a) A first buffer layer formed on the template layer; characterized by further comprising: b) The flattening cap layer is formed on the first buffer layer and is formed by epitaxial growth of lanthanum-strontium-manganese-oxygen materials through a pulse laser deposition technology, and the thickness of the flattening cap layer is 20-100 nanometers.
  2. 2. The composite buffer layer structure for high temperature superconducting tape of claim 1, wherein the flattened cap layer has a thickness of 20-50 nm.
  3. 3. The composite buffer layer structure for high temperature superconducting tape of claim 1, wherein the root mean square surface roughness of the planarized cap layer is less than 1 nanometer.
  4. 4. The composite buffer layer structure for high-temperature superconducting tape of claim 1, wherein the planarized cap layer is formed by epitaxial growth at 600-800 ℃ and an oxygen partial pressure of 10-200 mTorr by pulse laser deposition.
  5. 5. The composite buffer layer structure for high temperature superconducting tape of claim 1, wherein the template layer is a MgO layer prepared by ion beam assisted deposition.
  6. 6. The composite buffer layer structure for high temperature superconducting tape of claim 1, wherein the template layer is a NiW alloy layer and an oxide layer thereon prepared by a rolling-assisted biaxial texture technique.
  7. 7. The composite buffer layer structure for high temperature superconducting tape of claim 1, wherein the first buffer layer is CeO 2 .
  8. 8. The composite buffer layer structure for high temperature superconducting tape of claim 1, wherein the first buffer layer is LaMnO 3 .
  9. 9. The method for preparing a composite buffer layer structure for a superconducting tape according to any one of claims 1 to 8, comprising the steps of: 1) Providing a metal base tape having a barrier layer, a biaxially-textured template layer, and a first buffer layer; 2) Placing the baseband in a PLD vacuum chamber, and heating to 600-800 ℃; 3) Introducing oxygen into the chamber, and controlling the oxygen partial pressure to be 10-200 mTorr; 4) And ablating the LMO or LSMO ceramic target material by using a pulse laser, and epitaxially growing an LSMO thin film with the thickness of 20-100 nanometers on the first buffer layer to form the flattening cap layer.
  10. 10. A superconducting tape, comprising the composite buffer layer structure according to any one of claims 1 to 8 and a (Cu, C) Ba 2 Ca 2 Cu 3 O y or (Cu, C) Ba 2 Ca 3 Cu 4 O y superconducting layer epitaxially grown on the planarizing cap layer.

Description

Composite buffer layer structure for high-temperature superconducting tape, preparation method of composite buffer layer structure and superconducting tape Technical Field The invention relates to a composite buffer layer structure for a high-temperature superconducting tape, a preparation method thereof and a superconducting tape, and belongs to the technical field of high-temperature superconducting materials. Background The high-temperature superconducting material refers to an oxide ceramic material with a critical temperature significantly higher than that of a traditional low-temperature superconductor, and the discovery opens a way for realizing superconducting application in a liquid nitrogen temperature region. Such materials, particularly Rare Earth Barium Copper Oxide (REBCO) systems, have shown great potential in the fields of electricity and energy. However, the key to its commercial application is how to make brittle superconducting ceramics into flexible long tapes with high current carrying capacity, which has led to coated conductor technologies based on flexible metallic base tapes. For example, patent publication No. CN 100550453C discloses a resistive current limiting device with a strip-shaped high critical temperature superconductor. The strip-shaped superconductor of the resistance current limiting device comprises at least one normally conductive substrate strip, a buffer layer, a high Tc superconducting layer formed by AB 2Cu3OX type oxide and a protective layer, wherein the buffer layer forms a transition resistance of 10 -3Ωcm2 at most between the substrate strip and the superconducting layer, A is rare earth metal including one hundred million, and B is rare alkaline earth metal. Specifically, the buffer layer is one of lanthanum manganese oxide, strontium ruthenium oxide, lanthanum nickel oxide and indium tin oxide. The early second generation high temperature superconducting (2G-HTS) technology represented by this patent employs the basic architecture of "metal substrate strip + buffer layer + REBCO superconducting layer", but the buffer layer design has clear limitations. The device aims to solve the core problem that a traditional insulating buffer layer (such as CeO 2) is easy to break down by high voltage when the current-limiting device is out of time, and adopts a buffer layer material (such as lanthanum manganese oxide) with specific conductivity, so that a lower transition resistance is formed between the superconducting layer and the metal substrate strip, potential balance is realized, and breakdown is avoided. However, this solution, while pursuing improved electrical performance, ignores the critical structural function of the buffer layer as a template for epitaxial growth. The buffer layer mainly serves the electric bypass requirement, and has the defects of high-quality biaxial texture, ultra-smooth surface morphology, excellent lattice matching degree with the superconducting layer and the like required by modern high-performance superconducting tapes. This early second generation tape buffer technology, which has texture quality, surface flatness, and capability of inducing epitaxial growth, may not meet the current requirements for the preparation of ultra-high critical current density superconductors (especially novel copper-carbon-based superconductors that are extremely sensitive to growth conditions). In order to systematically overcome the defects of the early second-generation strips in the aspects of texture quality, superconducting layer epitaxial growth quality and the like, a more advanced multilayer structure system is developed. The second generation high temperature superconducting (2G-HTS) tapes currently generally employ a more precise layered structure of a flexible metal base tape (e.g., hastelloy) with a barrier layer (e.g., al 2O3), a textured template layer (e.g., IBAD-MgO), a buffer layer (e.g., laMnO 3, CeO2, etc.), and a superconducting layer (e.g., REBCO) deposited sequentially. The system aims to precisely control the crystal orientation by introducing a special textured template layer (such as IBAD-MgO) and an optimized buffer layer, and provides a nearly perfect epitaxial growth template for the superconducting layer, thereby remarkably improving the current carrying performance. In recent years, a novel copper-carbon-based high-temperature superconductor (Cu, C) Ba 2Ca2Cu3Oy or (Cu, C) Ba 2Ca3Cu4Oy has been attracting attention because of its excellent current-carrying performance under a high magnetic field. But its high quality epitaxial growth is strongly dependent on the surface quality and lattice size matching of the ribbon buffer layer. Currently, the surface of the buffer layer (such as CeO 2 or LaMnO 3) of a commercial strip generally has roughness on the nanometer scale, protrusions caused by grain boundary trenches or island growth modes, and in-plane lattice dimensions that differ greatly from those of copper-carbon-base