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Laser Texturing of Ceramic Superconductors

IP.com Disclosure Number: IPCOM000036792D
Original Publication Date: 1989-Oct-01
Included in the Prior Art Database: 2005-Jan-29
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Engler, EM: AUTHOR [+4]

Abstract

Bulk high Tc ceramic superconductors, based on Y1Ba2Cu3Ox and other related materials, show inferior critical properties compared to single crystals and thin films due to anisotropic electrical character and poor intergrain contacts. The grain morphology of these rare earth ceramics can be altered by melt texturing with a CW laser to enhance their superconducting properties. By rastering the laser at appropriate power densities and scan speeds, a crystallization front is formed and propagated over the surface of the bulk superconductor to give dense and aligned microstructures with improved critical properties.

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Laser Texturing of Ceramic Superconductors

Bulk high Tc ceramic superconductors, based on Y1Ba2Cu3Ox and other related materials, show inferior critical properties compared to single crystals and thin films due to anisotropic electrical character and poor intergrain contacts. The grain morphology of these rare earth ceramics can be altered by melt texturing with a CW laser to enhance their superconducting properties. By rastering the laser at appropriate power densities and scan speeds, a crystallization front is formed and propagated over the surface of the bulk superconductor to give dense and aligned microstructures with improved critical properties.

Pellets of Y1Ba2Cu3Ox were irradiated with a divergent beam from an argon laser scanned at 200 microns per second. The focal length of the lens was 90 mm with 120 mm from the lens to sample to give a spot size of approximately 0.5 mm on the sample. SEM analysis of irradiated area showed highly textured surface with much finer grain structure and extended rod-like grains aligned along the direction of the laser scan. To fully reoxygenate the textured area, the samples were annealed under oxygen atmosphere from 900oC to 920oC at
1.3oC/hour, followed by cooling to 600oC (53.3oC/hour) then to 300oC
(3.1oC/hour), and finally to room temperature. Annealed samples showed superconducting transitions at 94oK (onset) and zero resistance at 91oK.

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