LAMNO3 PEROVSKITE THIN-FILM DEPOSITION, FROM AQUEOUS NITRATE SOLUTIONS OF LA AND MN, IN A LOW-PRESSURE PLASMA EXPANDED THROUGH A NOZZLE (PETN)

A new low-pressure plasma coating process was developed using an induc tively coupled radio-frequency plasma, expanded through a nozzle (PETN ) and aqueous metallic salt injection in a pulsating mode. LaMnO3.15 p erovskites were deposited on quartz and YSZ substrates, in an Ar+O-2 p lasma using La(NO3)(3) and Mn(NO3)(2) aqueous precursors. The microcry stalline structure of the deposits was investigated by X-ray diffracti on (XRD) and transmission electron microscopy (TEM)-XRD. The aerosol p assing the r.f. Ar+O-2 plasma produces a shock wave prior to the nozzl e, evaporating the excess H2O and decomposing the water and nitrate co mpounds. The molecular spectra of LaO, MnO and OH show that the high r eactive plasma medium combined with a shock wave, accelerate the disso ciation oxidation kinetics. These results were confirmed by quadrupole mass spectrometry measurements. Laser doppler anemometry measurements also showed a regular and reproducible pulsed injection. (C) 1997 Els evier Science S.A.