ISOTHERMAL PRODUCTION OF UNIAXIALLY TEXTURED YBCO SUPERCONDUCTORS USING CONSTITUTIONAL GRADIENTS

Uniaxially textured samples of bulk (RE)BaCuO were melt-grown in an is othermal furnace utilizing the influence of different rare earth compo unds on the peritectic temperature of (RE)BaCuO. A suitable geometric arrangement of different (RE)Ba2Cu3Ox compounds during heat treatment leads to a specific diffusion profile of the respective RE elements. A ccording to the distinct peritectic temperatures of the different RE-s ystems, a monotonous decrease in peritectic temperature could be estab lished. This gradient determines the direction of crystallization duri ng isothermal cooling and moreover governs the selection mechanism res ulting in preferred c-axis growth. In contrast to texturing samples in external gradients, the use of a layered structure of different (RE)B a2Cu3Ox compounds allows a tailored texturing or textured coating even of complex shaped products and opens up a variety of interesting pers pectives for the production of long length wires and perhaps even of l arge grained bulk material.