Fabrication of YBCO thin flims by pulsed laser deposiyion technique and their charcterization

Abstract

This thesis focuses on pulsed laser deposition (PLD) system, fabrication of high temperature superconducting YBCO thin films and their characterization. In this study, the electrical and structural studies performed on laser deposited YBCO films have shown that films produced by PLD. The thin films were characterized in detail by employing structural XRD, SEM, EDX and AFM and electrical ( R-T) measurements. During this work, pulsed laser deposition system used to grow superconducting thin film on MgO single crystal substrate. Firstly PLD system was carried out by using different growth parameters. Deposited films was cooled down in situ under an oxygen atmosphere at a given pressure. The deposition tecnique has emerged as a very powerful method to make composition and microstructure controlled superconducting YBCO films.Thanks to rapid heating and evaporation of the target and interaction of the laser beam with evaporated materials leading to formation of a high temperature plasma PLD system is different from other thin film growth system.However, major problem was particulates emmission which was shown SEM,we solved this problem by chaning distance between target and substrate, and laser power. Furthermore Electron Dispersive X-Ray Spectroscopy (EDX) method was used to identify the chemical contents of the films.The relation between critical temperature and oxygen deficieny was investigated by means of electrical resistance R(T) and x-ray diffraction measurements.Finally, our results were compared to literature and explanied similarites.