Superconducting Nd/sub 1.85/Ce/sub 0.15/CuO/sub 4-y/ thin films and heterostructures on sapphire

Superconducting Nd/sub 1.85/Ce/sub 0.15/CuO/sub 4-y/ (NCCO) thin films have been made on yttria-stabilized zirconia (YSZ) buffered sapphire. The films are epitaxially grown and highly in-plane oriented. X-ray diffraction shows the c-axis of the film normal to the surface of the substrate. The width of rocking curve is 0.2/spl deg/ and the RBS channeling yield is 9%, indicating high crystallinity of the film. Cross-sectional transmission electron microscopy images reveal a sharp interface between NCCO and YSZ. The microwave surface resistance of NCCO films on YSZ buffered sapphire at 9.6 GHz was measured and a value of 80 /spl mu//spl Omega/ (at 4.2 K in zero DC magnetic field) was obtained, which is comparable to Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-y/ (YBCO) films at the same reduced temperature. A trilayer structure of YBCO/SrTiO/sub 3//NCCO on YSZ buffered sapphire has been fabricated with all layers oriented, in which both the YBCO and NCCO layers are superconducting.<
>