Artificial chessboard like textured YBCO films
Introduction
The study of artificial thin film high Tc texture structures is important in order to understand the transport properties of natural granular high Tc films [1] and to carry out the experimental confirmation of d-wave pairing symmetry in cuprate superconducting materials [2]. In addition, artificial texture influences on the optical properties of high Tc thin films with potential implication in the field of terahertz application [3]. In the present paper, we report on results of experimental investigation of electro-physical and magnetic properties of chessboard like structure YBCO film realized by the homo-biepitaxial technique.
Section snippets
Sample fabrication
The homo-biepitaxial growing is based on a 45° in-plane rotation of the grown YBCO films with respect to the substrate orientation realized by using a thin YBCO buffer layer deposited at a temperature (∼600 °C) out of the superconducting phase condition and lower than the optimal value (800 °C) [4]. Yttria-stabilized ZrO2 (YSZ) single crystal of (1 0 0) orientation was used as a substrate. YBCO films were deposited by dc magnetron sputtering with time modulated power as described in details in Ref.
Electro-physical measurements
Four electrodes (one to each corner) were connected to the square shape samples of 2 × 2 mm2 with and without chessboard like texture. Voltage–current ratio for opposite pairs of electrodes was measured as a function of temperature (T) in order to evaluate both the temperature associated with a full superconducting transition and the resistivity at T = 200 K (ρ(200 K)) calculated by Montgomery method [6]. For each sample the measurements were done for two orthogonal sides. The chessboard like
Acknowledgements
This work is partially supported by MIUR under the project “Sviluppo di componentistica avanzata e sua applicazione a strumentazione biomedica” and under the project FIRB-RBAU01PYB3.
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