Abstract
To obtain Tl-1223 wires with a high critical current density (Jc), Tl-1223 layers are necessary to orient each other biaxially with the a-axis. The cube-textured silver tapes can be successfully prepared as the substrate for realizing the well-oriented Tl-1223 layer.
The cube texture of silver tape was formed by heat treatment at temperatures higher than 600°C after rolling at an intermediate temperature. The full width at half maximum of X-ray diffraction φ-scan of the tape was typically 6°. The homogeneously textured structure was obtained over the 15 m long tape.
The Tl-1223 thin layer was prepared on the cube-textured silver tape by spray pyrolysis method. The degree of the a-axis orientation of Tl-1223 layer was improved by the substrate effect. Due to this biaxial texturing, the grain boundary characteristics were improved, that is, the Jc was as high as 1.5×104 A/cm2 at 77 K under an external field of 1 T.
The present study demonstrated that the Tl-1223 long scale wires with improved biaxial orientations can be manufactured by a combination of the simple heat treatment process for the cube-textured silver tape and the mass-productive spray pyrolysis method for the biaxially oriented Tl-1223 thin layer.
