COMPREHENSIVE X-RAY-DIFFRACTION STUDY OF YBA2CU3O7-DELTA THIN-FILMS

In situ annealed high temperature superconducting YBa2Cu3O7-delta thin films have been deposited on an MgO (100) substrate from a single sto ichiometric target using DC magnetron sputtering. The films were chara cterized by X-Ray diffraction (XRD) and scanning electron microscopy ( SEM) techniques. The effect of varying substrate temperature, T-5, and O-2/Ar ratio on lattice parameters and on the degree of orientation o f the films were examined. Both c- and a-lattice parameters decreased with increasing T-c. The reduction of c and a-lattice parameters as we ll as the oxygen deficiency in the films, delta, obey general (T-s - T -0)(-4) behavior. We develope a new method to measure a more accurate way to find the degree of preferrential orientation along c and a-axis of the deposited films, (Delta V-006/Delta V-200), at different T-c b y using X-ray diffraction theory and JCPDS files to obtain \ F-(006)/E ((200)) \(2). At T-s = 735 degrees C, the volume fraction along the c- axis was found to be Delta V-c approximate to 5.5 x Delta V-a correspo nding to 85% of grains having preferred orientation along c-axis. In a ddition, we have also measured FWHM of the (006) and (200) Peaks by va rying T-s. The thickness of the grains were estimated at different sub strate temperature using the Scherrer formula.