Dependence of perovskite/pyrochlore phase formation on oxygen stoichiometry in PLT thin films

Journal Article · Tue Mar 01 00:00:00 EST 1994 · Journal of Materials Research; (United States)

DOI:https://doi.org/10.1557/JMR.1994.0699· OSTI ID:5186040

Fox, G R; Krupanidhi, S B ^[1]

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1. Materials Research Laboratory, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

Thin films in the Pb--La--Ti--O (PLT) system were prepared under two different oxygen partial pressure ([ital P][sub O[sub 2]]) conditions by multi-ion-beam reactive sputtering (MIBERS). The oxidation of the depositing species was determined from the deposition rate dependence on [ital P][sub O[sub 2]] and the [ital P][sub O[sub 2]] dependence of the positive secondary ion emission from the sputtering targets. Films deposited at high [ital P][sub O[sub 2]] ([ital P][sub O[sub 2]] greater than the critical partial pressure for oxidation of the Pb target surface) were fully oxidized, and they formed the pyrochlore phase during annealing. The low [ital P][sub O[sub 2]] condition ([ital P][sub O[sub 2]] less than or equal to the critical partial pressure for oxidation of the Pb target surface) caused sputtering of incompletely oxidized Pb species, and the resulting oxygen deficient films produced phase-pure perovskite. The formation of the pyrochlore phase at high [ital P][sub O[sub 2]] and the perovskite phase at low [ital P][sub O[sub 2]] is independent of Pb content within the film; the phase formation is dependent on the oxidation state of the Pb, which is sensitive to both the [ital P][sub O[sub 2]] and the sputtering rate of the Pb. A perovskite/pyrochlore phase formation model (PPFM) that incorporates annealing time, temperature, and heating rate, and thin film oxygen deficiency was developed to explain the formation of the perovskite and pyrochlore phase during post-deposition annealing of PLT thin films.

• DOE Contract Number: AC05-84OR21400
• OSTI ID: 5186040
• Journal Information: Journal of Materials Research; (United States), Vol. 9:3; ISSN 0884-2914
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
LANTHANUM OXIDES
ANNEALING
PHASE STUDIES
SPUTTERING
LEAD OXIDES
TITANIUM OXIDES
ION BEAMS
OXYGEN
PARTIAL PRESSURE
PEROVSKITES
PYROCHLORE
THIN FILMS
BEAMS
CHALCOGENIDES
ELEMENTS
FILMS
HEAT TREATMENTS
LANTHANUM COMPOUNDS
LEAD COMPOUNDS
MINERALS
NONMETALS
OXIDES
OXYGEN COMPOUNDS
RARE EARTH COMPOUNDS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360202* - Ceramics
Cermets
& Refractories- Structure & Phase Studies