Thick film biaxially textured YBCO coated tape conductors prepared using magnetic grain alignment

We report a new approach to the preparation of biaxially textured YBCO coated tape conductors. Using a dynamic magnetic grain alignment technique, a biaxially aligned dispersion of orthorhombic Y-247 powder is settled on untextured silver substrates. In subsequent heat treatment the Y-247 is transformed to Y-123 and CuO involving a partial melt. Critical current densities at 77 K in self-field of up to 5000 A/cm/sup 2/ have been obtained in films from 10 to 30 /spl mu/m thick. There is a clear enhancement of J/sub c/ relative to identically prepared untextured or uniaxially textured samples. J/sub c/ appears to be limited at present by the difficulty of achieving fully densified films while retaining biaxial texture. Provided significant improvements in J/sub c/ can be obtained this method offers an alternative to coated tape processes based on epitaxial growth which does not demand textured substrates and can give much higher fill factors. The grain alignment technique is quite general for materials with anisotropic magnetic or electric susceptibility and can therefore be utilised in a wide range of applications.