Comprehensive X-Ray Diffraction Study of YBa 2Cu 3O 7-δ Thin Films

Abstract

In situ annealed high temperature superconducting YBa2Cu3O7-δ 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, T s, 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 T s. The reduction of c and a-lattice parameters as well as the oxygen deficiency in the films, δ, obey general (T s - T0)-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, (ΔV006/ΔV200), at different T s by using X-ray diffraction theory and JCPDS files to obtain ∣F(006)/F(200)∣2. At T s=735°C, the volume fraction along the c-axis was found to be ΔVc≈5.5 ×ΔVa corresponding to 85 grains having preferred orientation along c-axis. In addition, we have also measured FWHM of the (006) and (200) peaks by varying T s. The thickness of the grains were estimated at different substrate temperature using the Scherrer formula.