Transport and noise in YBa2Cu307 ramp junctions and 2-dimensional quantum interference filters

11/09/2008

In this project Josephson ramp junctions based on the high-transition temperature superconductor YBa2Cu3O7 (YBCO) with controlled interface and barrier properties shall be realized. Using high-qualitaty YBCO ramp junctions, we want to reach two goals: (i) systematic experimental investigations of electric transport and noise, combined with the spatially resolved analysis by means of low-temperature scanning electron microscopy (LTSEM) and theoretical modeling based on the quasiclassical Eilenberger equations shall provide an understanding of the transport properties of ramp junctions from a d-wave superconductor, with tailored interfaces and barriers. (ii) Two-dimensional (2D) superconducting quantum interference filters (SQIFs) shall be fabricated and investigated. SQIFs are Josephson interferometers which consist of intentionally irregular arrays of superconducting loops, designed according to specific statistical distributions. Such networks provide a tailored characteristic response to absolute magnetic fields, which are detectable wiht extremely high sensitivity, linearity and dynamic range.