Fabrication of Lanthanum Manganese Oxide Thin Films on Yttria-Stabilized Zirconia Substrates by a Chemically Modified Alkoxide Method

Abstract

Perovskite-type thin films of lanthanum manganese oxide (LaMnO 3 ) were prepared on yttria (8%) stabilized zirconia substrate by the sol-gel process from an alkoxide solution of lanthanum isopropoxide (La(O-i-C 3 H 7 ) 3 ) and manganese isopropoxide (Mn(O-i-C 3 H 7 ) 2 ). The alkoxide solution was chelated with 2-ethyacetoacetate, and further modified with polyethylene glycol (PEG). The obtained LaMnO 3 thin film was transparent and macroscopically crackless. X-ray diffraction, differential thermal analysis-thermogravimetry analysis, and scanning electron microscope observations indicated that single-phase LaMnO 3 thin films with a grain size of 80 to 100 nm are formed when a spin-coated LaMnO, gelled film is heated at 600°C for 1 h. The porous and homogeneous grain structure with a grain size of <100 nm can be obtained when the LaMnO 3 gelled film is heated at 600° and 800°C. It was considered that PEG might accelerate the crystallization of the perovskite phase, which indicates that PEG assists the formation of the La-O-Mn frame network during partial hydrolysis and condensation reactions in sol-gel processes.