Spectral-Component Monitoring of the Plumes Generated during the Deposition of RE(Y, Nd) Ba2Cu3O7−x Films by Pulsed Laser Ablation

Abstract

ABSTRACTYba2Cu3OT7−x (Y123) and NdBa2Cu3O7−x (Nd123) thin films were deposited by PLD using a 248 nm wavelength KrF excimer laser. The emission spectra PLD process control techniques developed to grow reproducibly high quality Y123 thin films were also applied to the Nd123 depositions. The time-resolved spectral components of plumes generated from Y123 and Nd123 targets at the same deposition conditions were compared. When the two targets were mounted at the same distance from the substrate heater, the spectral emissions at 327 ± 5 nm (Cu*) were essentially identical for similar laser pulse energies and other deposition conditions (150 mTorr oxygen pressure, 760°C substrate heater temperatures, etc.). High quality Nd 123 films (Tc ˜93 K, Jc > 2x 106 A/cm2) are considerably more difficult to produce than those of Y123. Deposition conditions associated with PLD of high quality Y123 films produce very poor Nd 123 films. This observation is consistent with the belief that the nucleation and growth of Nd 123 are significantly different than that of Y 123.