The effect of heat treatment temperature on superconductivity of Bi-2212/YBCO heteroepitaxial structure fabricated by chemical solution deposition approach

Abstract

A planar-type heteroepitaxial junction with high-Tc superconducting YBa2Cu3O7−δ(YBCO) and Bi2Sr2CaCu2O8+δ(Bi-2212)electrodes has been prepared. Bi-2212/YBCO heteroepitaxial structure without an insulating layer was deposited on LaAlO3 (LAO) monocrystalline substrates by an all chemical solution deposition approach. Furthermore, the effect of heat treatment temperature on the superconductivity of Bi-2212/YBCO planar-type junction has been studied. Two superconducting transition steps in the R-T curves of Bi-2212/YBCO bilayer films prepared at 780 ℃ were clearly observed. The superconducting critical transition temperatures (Tc) of lower YBCO and upper Bi-2212 were about 91 K and 80 K, respectively. It was found that the critical current(Ic) was about 0.4 mA at 10 K and the superconductivity of planar-type junction strongly depend on the heat treatment temperature.