THIN-FILMS OF RARE-EARTH (Y, LA, CE, PR, ND, SM) OXIDES FORMED BY THE SPRAY-ICP TECHNIQUE

Thin films of Y2O3, La2O3, CeO2, PrO2, Nd2O3 and Sm2O3 were synthesized by injecting ultrasonically atomized metal nitrate solutions into a high temperature inductively coupled RF plasma above 5000 K generated under atmospheric pressure (the spray-ICP technique). Fused quartz plates and single crystal sapphire plates giving no background X-ray reflection peaks were used as substrates. About 0.4-mu-m thick transparent films could be prepared by 10 min of running. The films of CeO2 and PrO2, both belonging to the cubic fluorite type, revealed (100) and (111) orientations, respectively. With the remaining oxides having A (hexagonal), B (monoclinic) and C (cubic) rare-earth structures, film orientations were A (001) for La2O3, A (001) + C (111) for Nd2O3, and C(111) for Y2O3. SM2O3 films were composed of a phase with C(111) and an extra phase with an orientation close to (001) of A-Sm2O3 or its equivalent, (201BAR) of B-Sm2O3.