Electrical noise in YBaCuO superconducting thin-films with differing axes of orientation

In this paper we present a comparison of dc and electrical noise characteristics of high-temperature superconductor thin-films with differing preferred axes of orientation. Four thin-film samples were studied, two of c-axis and two of a-axis orientation. All films were YBaCuO superconducting material on SrTiO₃ substrates. The R-T, I-V, and electrical noise properties were measured for each of the films and comparisons were made between them. The experimental data was compared with current hypotheses on conduction and crystal structure. Our results show that from the dc and electrical noise measurements that the c-axis films are much better than a-axis films in applications where sensitivity and sharp transition are important factors. These results also show that preliminary results fit a p-noise model for a 2-D normal conductor-superconductor percolation network