Preparation and transport properties of highhyphen;Tcsuperconducting thick films

摘要

We have prepared thick films of highTcsuperconductors on a variety of substrates: SrTiO3, BeO, Zr(Ca)O2, alumina, and sapphire. The powder of the YBa2Cu3O7minus;dgr;compound is mixed with an organic solvent and painted on the substrates. The films are then dried and fired. We have studied the effect of the substrate and of the firing temperature on the superconducting properties of the films. We found an optimum firing temperature of 990thinsp;deg;C. The films prepared are superconducting withTc(R=0) as high as 82 K. We discuss the shape of the resistancehyphen;versushyphen;temperature curves as well as the temperature dependence of the critical currents of these films.