Schröder S, Fritze H, Bishop S, et al. Thin-film nano-thermogravimetry applied to praseodymium-cerium oxide films at high temperatures[J]. Applied Physics Letters, 2018, 112(21): 213502.

ABSTRACT

High precision measurements of oxygen nonstoichiometrydin thin film metal oxides MaOb6datelevated temperatures and controlled oxygen partial pressurespO2are reported with the aid ofresonant microbalances. The resonant microbalances applied here consisted ofy-cut langasite(La3Ga5SiO14) and CTGS (Ca3TaGa3Si2O14) piezoelectric resonators, operated in the thicknessshear mode at5 MHz. Measurements of variations indof Pr0.1Ce0.9O2-d(PCO) films are reportedfor the oxygen partial pressure range from 108bar to 0.2 bar at 700C, and these results werefound to be in good agreement with previously reported oxygen nonstoichiometryddata derivedfrom chemical capacitance studies. The PCO thin-films were deposited via pulsed laser depositionon both sides of the resonators, whose series resonance frequency was tracked, converted into masschanges and, finally, into nonstoichiometry. The nonstoichiometry was observed to reach a plateauas the oxygen partial pressure dropped below about 105bar, the behavior being attributed to thefull reduction of Pr to the trivalent state. These resonators enable stable operation up to tempera-tures above 1000C, thereby maintaining high mass resolution suitable for determining oxygennonstoichiometry variations in thin films deposited on such resonators. For the given experimentalconditions, a mass resolution of50 ng was achieved at 700C with the CTGS resonator