In situ creation of nanoparticles from YBCO by pulsed laser deposition

Nanoparticles created by the laser ablation of YBCO are reported. The experimental procedure entailed pulsed laser deposition (PLD) of YBCO at a high background pressure of 5 Torr O-2. The sizes of the nanoparticles range from similar to3 to 5 nm and are typical of the depositions made using laser energies of 50 mJ per pulse. Optical emission spectroscopy was used to characterize the PLD plume. Under nanoparticle deposition conditions, the visible plume emission is very weak. Even so, the distribution among electronically excited states cannot be described by a single temperature. The plume remains collisionally dynamic even at high pressures and low laser energies and retains considerable excitation when nanoparticles are formed. (C) 2002 Published by Elsevier Science B.V.