Comparison of texture development and superconducting properties of YBCO thin films prepared by TFA and PLD processes

Although pulsed laser deposition (PLD) is one of the most reliable techniqu es for fabricating YBa2Cu3Ox (YBCO) thin films with high critical current d ensity (J(c)), metal organic decomposition (MOD), including the trifluoroac etate (TFA) process, is attracting more interest because of its potential f or scale-up and cost-effectiveness. In general, PLD samples have higher J(c ) values than those of TFA samples. In this study, we deposited YBCO films on LaAlO3 single-crystal substrates by TFA and PLD, respectively. Performan ce of the two samples was compared to investigate possible causes that lead to the different J(c) values. In-plane and out-of-plane texture was evalua ted quantitatively by phi and omega scan, respectively. The FWHMs of phi an d omega scans for the TFA sample were comparable to those of the PLD sample , indicating that TFA films follow the substrate texture precisely. Raman s pectra were measured to estimate grain connectivity, texture, and second-ph ase formation. The properties of the samples are almost identical, except f or the intensity of the BaCuO2 Raman peaks. Microstructure observation by S EM showed that TFA films were generally more porous and smaller-grained tha n PLD samples. Considering these results, the difference in J(c) values bet ween TFA and PLD samples (1.3 and 3 MA/cm(2), respectively) in this experim ent is partly attributed to the more porous microstructure of the TFA sampl es. (C) 2001 Elsevier Science B.V. All rights reserved.