PEROVSKITE-TYPE LANTHANUM CHROMIUM-BASED OXIDE-FILMS PREPARED BY ULTRASONIC SPRAY-PYROLYSIS

Ultrasonic spray pyrolysis was used to form 2-8 mu m thick LaCrO3 films on different substrates from La(CrO4)(NO3). nH(2)O precursor films. There was an optimum substrate temperature for the formation of uniform precursor films by the spray pyrolysis. When the substrate temperature was lower than 250 degrees C, dry precursor films were not formed, while above 250 degrees C the deposition rate decreased with substrate temperature. The precursor films were converted to perovskite-type oxide films by heat treatment at 800 degrees C in a nitrogen atmosphere. Both A-site substituted (La0.8Ca0.2) CrO3 and B-site substituted La(Cr-0.5 Mn-0.8)O-3 oxide films were formed in a similar manner. Electronic conductivity of the oxide films was improved by repetitions of the spray pyrolysis and heat treatment in nitrogen.