Integrated experimental and modeling study of the ionic conductivity of samaria-doped ceria thin films

Journal Article · Mon Dec 12 04:00:00 EST 2011 · Solid State Ionics

DOI:https://doi.org/10.1016/j.ssi.2011.10.007· OSTI ID:1031426

Sanghavi, Rahul P; Devanathan, Ramaswami; Nandasiri, Manjula I; Kovarik, Libor; Thevuthasan, Suntharampillai; Prasad, Shalini

Oxygen diffusion and ionic conductivity of samaria-doped ceria (SDC) thin films have been studied as a function of composition using experiment and atomistic simulation. SDC thin films were grown on Al2O3 (0001) substrates by oxygen plasma-assisted molecular beam epitaxy (OPA-MBE) technique. The experimental results show a peak in electrical conductivity of SDC at 15 mol% Sm2O3. The oxygen diffusion coefficient obtained from molecular dynamics simulation of the same system shows a peak at about 13 mol% Sm2O3. The activation energy for oxygen diffusion was found to be in the range from 0.8 to 1.0 eV by simulations depending on the Sm2O3 content, which compares well with the range from 0.6 to 0.9 eV given by the experimental work. The simulations also show that oxygen vacancies prefer Sm3+ ions as first neighbors over Ce4+ ions. The present results reveal that the optimum samaria content for ionic conductivity in single crystals of SDC is less than that in polycrystals, which can be related to the preferential segregation of dopant cations to grain boundaries in polycrystals.

• Research Organization: Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1031426
• Report Number(s): PNNL-SA-76714; 30507; 25414a; KP1704020
• Journal Information: Solid State Ionics, Journal Name: Solid State Ionics Vol. 204-205; ISSN SSIOD3; ISSN 0167-2738
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ACTIVATION ENERGY
CATIONS
DIFFUSION
ELECTRIC CONDUCTIVITY
Environmental Molecular Sciences Laboratory
GRAIN BOUNDARIES
IONIC CONDUCTIVITY
MOLECULAR BEAM EPITAXY
MONOCRYSTALS
OXYGEN
POLYCRYSTALS
SEGREGATION
SIMULATION
SUBSTRATES
Samaria
THIN FILMS
VACANCIES
ceria
conductivity
crystal
doped
dynamics
films
molecular
simulation
single
thin