Superconducting Wire Manufacturing via Segmented Thin Film Deposition
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Solution Overview
Problem
Existing methods for manufacturing Y-based superconducting wires, such as PLD and MOCVD, face issues with high costs due to expensive equipment and saturation of superconducting current as the film thickness increases, primarily due to the growth of anisotropic crystals which do not contribute to improved critical current.
Innovation Solution
A method involving the deposition of multiple thin films of superconducting layers with a thickness between 10 nm and 200 nm on a metallic substrate, heated to a film deposition temperature of 700° C to 900° C, and then cooled, to prevent the formation of anisotropic crystals and maintain high critical current even with thicker films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the film thickness of the superconducting layer is increased to improve critical current, then the superconducting current improves linearly up to a certain thickness, but when the film thickness exceeds this certain thickness, the superconducting current becomes saturated due to the growth of anisotropic crystals
Solution Approach 1:
The superconducting layer is divided into multiple thin films with thickness of 10 nm to 200 nm each. By segmenting the total film thickness into multiple thin layers, the patent prevents the formation of anisotropic crystals that occur in thick single-layer deposits, while still achieving the desired total thickness for high critical current. Each thin film maintains c-axis oriented crystal growth, and the segmented structure allows the superconducting current to scale with total thickness without saturation.
2Ease of manufacture
If conventional MOCVD method is used to deposit thick superconducting layers, then the apparatus cost is reduced compared to PLD, but the superconducting current saturates when film thickness exceeds a certain value due to anisotropic crystal growth
Solution Approach 1:
The patent changes the deposition parameters by controlling each thin film to have a thickness of 10 nm to 200 nm, which is significantly thinner than conventional single-layer deposits. This parameter change in film thickness prevents the nucleation and growth of anisotropic crystals (a-axis and b-axis oriented crystals) that typically form in thicker deposits. The modified deposition parameters include heating the metallic substrate to film deposition temperature (700-900°C for YBCO), depositing the thin superconducting film, and then cooling the substrate, repeated multiple times to achieve the desired total thickness.
3Reliability
If PLD method is used to deposit superconducting layers, then the superconducting properties are maintained, but the apparatus becomes extremely expensive and requires extremely expensive laser equipment for industrial use
Solution Approach 1:
The patent replaces the expensive PLD laser system with a more economical MOCVD deposition system. While PLD uses expensive industrial lasers that are durable but extremely expensive, the invention employs MOCVD with standard deposition equipment that is more cost-effective for industrial production. The patent achieves comparable or superior superconducting properties through the thin-film segmented approach combined with controlled deposition and cooling cycles, making the manufacturing process more economically viable without sacrificing performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the production of superconducting wires with non-saturated critical current, enhancing crystallinity and preventing the growth of anisotropic crystals, thereby improving the superconducting properties without increasing costs or film thickness limitations.
Implementation Method 1
heating the metallic substrate to a film deposition temperature of a superconducting thin film
Implementation Method 2
depositing the superconducting thin film with a film thickness of 10 nm or more and 200 nm or less on the intermediate layer
Implementation Method 3
cooling the metallic substrate temperature below the film deposition temperature of the superconducting thin film
Data Source
AI summary
A method for manufacturing a superconducting wire material in which the superconducting current is not saturated even when a superconducting layer is made into a thick film, and a superconducting wire material. In the method a superconducting layer is formed on a metal substrate interposed by an intermediate layer, the method including heating the metal substrate up to the film-formation temperature of a superconducting film for forming the superconducting layer, forming a superconducting film having a film thickness of at least 10 nm and no more than 200 nm on the intermediate layer, and reducing the metal substrate temperature to a level below the film-formation temperature of the superconducting film, and the superconducting film-formation, including the heating, the film-formation, and the cooling, are performed a plurality of times.