SUPERCONDUCTING BI-SR-CA-CU-O FILMS FORMED BY DIFFUSION OF METALLIC BISMUTH ON SR2CA2CU4OY SUBSTRATES

초록

The superconducting low T(c) Bi2Sr2CaCu2O(y) films of 1-mu-m in thickness have been prepared on Sr2Ca2Cu4O(y) substrates by thermal evaporation of metallic Bi layer and heat treatment at 830-degrees-C for a few minutes in air. The transition behavior and morphology of the films were studied by resistivity measurements and scanning electron microscopy. The zero resistance temperature T(cz) and critical current density J(c) at 70 K were observed to be 78 K and 10(3) A/cm2, respectively. It is found that the superconducting films are formed by the reaction between liquid phase (Bi2O3) and solid phase (substrate), and that the dendrite structure is produced in the cross section of the films as it is generally observed in the liquid phase sintering.