Project Title:

Orientation of High Tc Superconductors by Optical Processing

Advanced-Fuel Research, Inc.
87 Church Street
P.O.  Box 380379
East Hartford, CT 06138-0379

93-1		04.07	9806			Amount Requested $69,956

Orientation of High Tc Superconductors by Optical Processing

Abstract:

The inability to fabricate copper-based superconductors capable of 
transporting or circulating high current densities over large 
volumes has severely limited applications for wires and levitation.  
Difficulties in texturing these ceramic materials is due to the 
requirement for nearly perfect grain boundaries resulting from the 
small quasi particle coherence lengths.  Control of the morphology 
and nature of defects or grain boundaries effecting vortex pinning 
is the key to expanding applications of these materials.  We 
propose a method to create rapid melting and solidification in the 
presence of a giant thermal gradient along the c-axis of 
mechanically aligned bulk YBa2Cu307-x substrates.  A fast-moving 
and directed, giant thermal gradient is energized by continuous 
wave C02 laser radiation.  Objectives are directed toward 
developing a technology for fabricating large structures of high Jc 
copper-based superconductors relevant to wire and levitation 
applications.  Experiments will be performed to define the best 
compositional pathways and optical parameters to control the 
ceramic morphology.  Large structures of textured ceramics with a 
high density of pinning sites will find numerous NASA applications 
for magnetically levitated static and dynamical bearing systems 
requiring large forces, restoring forces (stiffness) and minimal 
rotational drag forces.

A technology based on optical processing of bulk ceramic 
superconductors has great commercial potential for future markets 
in bearings, motors, generators, flywheel energy storage, 
electronics, micromachinery, medical applications (MRI, etc.), 
magnetic separators and MAGLEV transportation.  This technology is 
widely considered to be in an area of great importance for US 
international competitiveness.

High temperature superconductors; YBa2Cu3O7-x; Directional 
solidification by optical processing; Giant thermal gradients; 
continuous wave C02 lasers; magnetic levitation.