Superconductivity of YBa/sub 2/Cu/sub 3/O/sub 7//PrBa/sub 2/Cu/sub 3/O/sub 7/-superlattices

The preparation of heterostructures is a precondition for a large variety of high-T/sub c/ thin film devices. As a simple model system for high-T/sub c/ thin-film devices, the authors studied YBa/sub 2/Cu/sub 3/O/sub 7//PrBa/sub 2/Cu/sub 3/O/sub 7/-superlattices. High-quality superlattices show satellite peaks up to the 9/sup th/ order in X-ray diffraction diagrams. From comparison of the X-ray data with theoretical simulations the maximum amount of disorder and interdiffusion are deduced. Transmission electron microscopy (TEM) investigations of the films confirm the high degree of structural order. From resistive transition curves the authors determined thermal activation energies. The Arrhenius-plots are linear down to T/T/sub c/<0.5. From the dependence of the measured resistive and critical current on the angle between the magnetic field and the c-axis of the film, a two-dimensional behavior of the system is deduced. Even superlattices with a modulation Y:Pr=10:1 behave in this manner up to temperatures of 0.9 T/sub c/.<
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