SUPERCONDUCTING SR0.875ND0.125CUO2-DELTA THIN-FILMS

Single-phase Sr0.875Nd0.125CuO2-delta (SNCO) thin films of the ''infin ite-layer'' structure were fabricated by a pulsed-laser deposition tec hnique. The films directly grown on SrTiO3 (100) substrates had superc onductivity onset temperatures around 20 K, but zero resistances were not observed down to 4.2 K. The a-axis length of the film samples did not exceed the values reported for bulk SNCO samples. It was demonstra ted that, when deposited onto a Pr2CuO4 buffer layer formed on a SrTiO 3 substrate, the a-axis length of the thin film SNCO increased up to 0 .395 nm which was comparable to that for bulk SNCO. The film sample ex hibited a zero resistance state below 7 K. Thermoelectric-power measur ements indicated that the carrier density for the film deposited on a Pr2CuO4 buffer layer was higher than that for the film fabricated with out a buffer layer.