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CN-121992346-A - Target for PLD growth of CuC-1223 superconducting film, and preparation method and application thereof

CN121992346ACN 121992346 ACN121992346 ACN 121992346ACN-121992346-A

Abstract

The invention belongs to the technical field of high-temperature superconducting materials, and particularly relates to a target material for PLD growth of a CuC-1223 superconducting film, and a preparation method and application thereof, wherein the target material consists of Ba, ca, cu, O elements, the mol ratio of three metal elements of Ba, ca and Cu is 2 (2-3) (3.5-4.5), and the three metal elements of Ba, ca and Cu are uniformly distributed at a nanoscale. The PLD deposition is carried out by using the target provided by the invention, and plasma plume with stable components and accurate metering ratio can be provided, so that an epitaxial film with less impurity phase and high crystallization quality can be grown. The film can fully embody the intrinsic superconducting characteristic of CuC-1223 phase, obtain higher superconducting critical temperature (Tc) and more superior current carrying performance, and the preparation process has good reproducibility and strong target batch consistency, thereby providing a solid foundation for reliable and repeated preparation of the high-performance superconducting film.

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 target material for PLD growth of CuC-1223 superconducting film is characterized in that, The target material consists of Ba, ca, cu, O elements, wherein, Ba. The molar ratio of the Ca to the Cu is 2 (2-3) (3.5-4.5), Ba. The three metal elements Ca and Cu are uniformly mixed and distributed under the nanoscale.
  2. 2. A method of preparing a target according to claim 1, wherein a sol-gel method is employed, comprising the steps of: S1, dissolving soluble metal salts containing barium, calcium and copper into a solvent according to the molar ratio Ba, ca, cu=2 (2-3) and (3.5-4.5) to form a mixed salt solution; S2, adding a complexing agent into the mixed salt solution to form sol; S3, converting the sol into gel and drying to obtain a dried gel precursor; S4, presintering the dried gel precursor in an oxygen-containing atmosphere to obtain precursor powder; And S5, pressing, forming and sintering the precursor powder to obtain the target.
  3. 3. The method according to claim 2, wherein, In step S2, the complexing agent is an organic polyacid or a salt thereof.
  4. 4. A process according to claim 3, wherein, The organic polyacid is at least one selected from citric acid, ethylenediamine tetraacetic acid and tartaric acid.
  5. 5. The process according to any one of claim 2 to 4, wherein, In step S2, the ratio of the total moles of complexing agent to the moles of total metal ions is from 1:1 to 3:1.
  6. 6. The method according to claim 2, wherein, The soluble metal salt containing barium is barium nitrate or barium acetate; the calcium-containing soluble metal salt is calcium nitrate or calcium acetate; the soluble copper-containing metal salt is copper nitrate or copper acetate.
  7. 7. The method according to claim 2, wherein, In the step S4, presintering is carried out in an oxygen-containing atmosphere, the presintering is carried out at 300-500 ℃ for 2-5h; In the step S5, the sintering is carried out in an oxygen-containing atmosphere, the sintering temperature is 800-850 ℃, and the sintering time is 10-30 hours.
  8. 8. Use of the target according to claim 1 for preparing (CuC) Ba 2 Ca 2 Cu 3 O y superconducting films by pulsed laser deposition.
  9. 9. The use according to claim 9, wherein the (CuC) Ba 2 Ca 2 Cu 3 O y superconducting thin film prepared by pulsed laser deposition using the target has a critical onset temperature of superconductivity higher than 110K.
  10. 10. A superconducting device comprising a (CuC) Ba 2 Ca 2 Cu 3 O y superconducting film prepared by the method of any one of claims 8-9.

Description

Target for PLD growth of CuC-1223 superconducting film, and preparation method and application thereof Technical Field The invention belongs to the technical field of high-temperature superconducting materials, and particularly relates to a target material for PLD (programmable logic device) growth of a CuC-1223 superconducting film, and a preparation method and application thereof. Background Copper-based high temperature superconducting materials, in particular the (CuC) Ba 2Ca2Cu3Oy (CuC-1223) system, have been widely focused on the field of strong current applications due to their relatively high irreversible fields and critical current densities. To achieve its application potential, it is critical to obtain high quality epitaxial films. Pulsed Laser Deposition (PLD) technology is one of the mainstream methods of preparing such thin films, the principle of which is to ablate a target material with a laser to cause the target material components to be transported and deposited onto a substrate in the form of a plasma plume. Therefore, the quality of the target itself, particularly the uniformity and phase purity of its chemical components, directly determines the stability of the plasma plume, and thus has a decisive influence on the crystallization quality, phase composition and superconducting properties of the final film. At present, a traditional solid-phase reaction method is generally adopted for preparing the CuC-1223 phase target material in the field. The method generally uses BaCO 3、CaCO3, cuO and other powders as initial raw materials, mechanically mixes the raw materials according to a target stoichiometric ratio, and performs long-time sintering at high temperature (generally higher than 800 ℃) after ball milling and tabletting molding. This approach, while simple in process, has some inherent limitations. Because of the complex thermodynamic properties of the Ba-Ca-Cu-O quaternary system, the Ba, ca, cu, O four elements react directly in the solid state with differences in diffusion rates, making it difficult to directly form a single, stable CuC-1223 compound. During high temperature sintering, the system is more prone to follow local thermodynamic equilibrium, producing various thermodynamically more stable mesophases such as BaCuO 2、Ca2CuO3 and incompletely reacted CuO, etc. These side reaction products are present in the target in the form of micrometer-scale particles, resulting in the final target being essentially a mechanical mixture of multiple compounds, rather than a single phase material of uniform composition. When PLD deposition is carried out by using the target material with uneven components, plasma plumes ablated from different areas on the surface of the target material are scanned by laser spots, and the element composition of the plasma plumes can fluctuate along with laser striking on different phases such as BaCuO 2、Ca2CuO3, cuO and the like. Such unstable element supply can interfere with the ordered arrangement of atomic dimensions at the film growth interface, making the epitaxial growth process complex and difficult to control. As a direct consequence, a hetero-phase which does not match the host phase lattice structure is often introduced into the film produced. These hetero-phases not only destroy the continuity of the superconducting phase, form weak connection of current carrying capacity, but also introduce lattice defects and stress fields to become magnetic flux pinning centers or scattering centers, thereby significantly affecting the superconducting performance of the film, in particular leading to reduction of the critical temperature of the superconducting and increase of the transition width. Although researchers have attempted to improve uniformity by optimizing sintering temperature, time, atmosphere, and processes employing multiple grinding and sintering, the inherent limitations of solid-solid reaction mechanisms of solid-phase reaction methods have made it difficult to effectively solve the fundamental problem of uniform mixing of elements on an atomic/molecular scale. Therefore, the development of a novel target preparation technology capable of realizing the highly uniform distribution of Ba, ca and Cu elements is a direction worthy of deep exploration for improving the quality and performance consistency of the CuC-1223 superconducting film. Disclosure of Invention The application aims to overcome the defect of poor film superconducting performance caused by uneven element distribution and easy generation of impurity phases when a CuC-1223 superconducting film target material is prepared by adopting a solid phase reaction method in the prior art, and therefore, the application provides a target material for growing a CuC-1223 superconducting film by PLD, and a preparation method and application thereof, and the target material is used for overcoming the defects. In order to achieve the aim of the invention, the invention is realized by the fo