Comprehensive X-Ray Diffraction Study of YBa2Cu3O7-?Thin Films

In situ annealed high temperature superconducting YBa2Cu3O7-?thin films have been deposited on an MgO (100) substrate from a single stoichiometric target using DC magnetron sputtering. The films were characterized by X-Ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The effect of varying substrate temperature, Ts, and O2/Ar ratio on lattice parameters and on the degree of orientation of the films were examined. Both c- and a-lattice parameters decreased with increasing Ts. The reduction of cand a-lattice parameters as well as the oxygen deficiency in the films, ?, obey general (Ts- T0)-4behavior. We develope a new method to measure a more accurate way to find the degree of preferrential orientation along cand a-axis of the deposited films, (?V006/?V200), at different Tsby using X-ray diffraction theory and JCPDS files to obtain ?F(006)/F(200)?2. At Ts=735°C, the volume fraction along the c-axis was found to be ?Vc?5.5 ×?Vacorresponding to 85 grains having preferred orientation along c-axis. In addition, we have also measured FWHM of the (006) and (200) peaks by varying Ts. The thickness of the grains were estimated at different substrate temperature using the Scherrer formula.