Optimization of the ${\rm BaCeO}_{3}$ Concentration in YBCO Films Prepared by Pulsed Laser Deposition

A series of studies has been carried out on thin films prepared by pulsed laser deposition (PLD) from micro-grained targets of YBa₂Cu₃O_7-x (YBCO) to determine the effect of doping them with BaCeO₃ (BCO) in concentrations between 0-10 wt%. BCO has been found to increase J_c in e.g. melt-textured and bulk samples, but no systematic study with PLD thin films has been performed. Magnetometric measurements up to 8 T and down to 10 K as well as structural measurements with XRD and AFM were performed. J_c increased with doping and the highest J_c ´s were achieved with low dopant levels (2% and 4%), which varied according to the external field and temperature. T_c decreased when the dopant concentration was increased, similarly as in BaZrO₃ (BZO) doped films. However, the BCO growth process in the films was found to be different from the BZO and, furthermore, an interesting effect where the YBCO twin structure is altered was found around 6 wt% of BCO. The J_c results and a comparison with structural properties with increasing dopant level and optimally BZO-doped YBCO thin films are presented.