TY  - JOUR
AU  - Neilsen, Grace
AU  - Rosen, Peter F.
AU  - Dickson, Matthew S.
AU  - Popović, Marko
AU  - Schliesser, Jacob
AU  - Hansen, Lee D.
AU  - Navrotsky, Alexandra
AU  - Woodfield, Brian F.
PY  - 2021
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/6070
AB  - Doped ceria materials are ionic conductors currently under investigation for use in solid oxide fuel cells, catalysts, and other applications. We measured the heat capacity of several doped ceria samples from 1.8 K to 300 K to better understand their physical properties. The samples used in this study were either singly doped with Nd or Sm, or co-doped with both Nd and Sm. This work complements an earlier detailed study of their heats of formation and ionic conductivity. Here we provide the thermodynamic functions based on theoretical fits of our heat capacity measurements including Cp,m°, Δ0TSm°, Δ0THm°, and Φm°. We also detected splitting of nuclear magnetic states, which appeared as an upturn in the heat capacity below 10 K. We observed this phenomenon in all samples and provide calculations of the local magnetic field causing the splitting.
PB  - Elsevier
T2  - The Journal of Chemical Thermodynamics
T1  - Heat capacities and thermodynamic functions of neodymia and samaria doped ceria
VL  - 158
SP  - 106454
DO  - 10.1016/j.jct.2021.106454
ER  - 

@article{
author = "Neilsen, Grace and Rosen, Peter F. and Dickson, Matthew S. and Popović, Marko and Schliesser, Jacob and Hansen, Lee D. and Navrotsky, Alexandra and Woodfield, Brian F.",
year = "2021",
abstract = "Doped ceria materials are ionic conductors currently under investigation for use in solid oxide fuel cells, catalysts, and other applications. We measured the heat capacity of several doped ceria samples from 1.8 K to 300 K to better understand their physical properties. The samples used in this study were either singly doped with Nd or Sm, or co-doped with both Nd and Sm. This work complements an earlier detailed study of their heats of formation and ionic conductivity. Here we provide the thermodynamic functions based on theoretical fits of our heat capacity measurements including Cp,m°, Δ0TSm°, Δ0THm°, and Φm°. We also detected splitting of nuclear magnetic states, which appeared as an upturn in the heat capacity below 10 K. We observed this phenomenon in all samples and provide calculations of the local magnetic field causing the splitting.",
publisher = "Elsevier",
journal = "The Journal of Chemical Thermodynamics",
title = "Heat capacities and thermodynamic functions of neodymia and samaria doped ceria",
volume = "158",
pages = "106454",
doi = "10.1016/j.jct.2021.106454"
}

Neilsen, G., Rosen, P. F., Dickson, M. S., Popović, M., Schliesser, J., Hansen, L. D., Navrotsky, A.,& Woodfield, B. F.. (2021). Heat capacities and thermodynamic functions of neodymia and samaria doped ceria. in The Journal of Chemical Thermodynamics
Elsevier., 158, 106454.
https://doi.org/10.1016/j.jct.2021.106454

Neilsen G, Rosen PF, Dickson MS, Popović M, Schliesser J, Hansen LD, Navrotsky A, Woodfield BF. Heat capacities and thermodynamic functions of neodymia and samaria doped ceria. in The Journal of Chemical Thermodynamics. 2021;158:106454.
doi:10.1016/j.jct.2021.106454 .

Neilsen, Grace, Rosen, Peter F., Dickson, Matthew S., Popović, Marko, Schliesser, Jacob, Hansen, Lee D., Navrotsky, Alexandra, Woodfield, Brian F., "Heat capacities and thermodynamic functions of neodymia and samaria doped ceria" in The Journal of Chemical Thermodynamics, 158 (2021):106454,
https://doi.org/10.1016/j.jct.2021.106454 . .

TY  - JOUR
AU  - Neilsen, Grace
AU  - Rosen, Peter
AU  - Dickson, Matthew
AU  - Popović, Marko
AU  - Schliesser, Jacob
AU  - Hansen, Lee
AU  - Navrotsky, Alexandra
AU  - Woodfield, Brian
PY  - 2020
UR  - https://cer.ihtm.bg.ac.rs/handle/123456789/6064
AB  - It has been previously reported in the literature that the vacancy concentration in a solid can be estimated using the linear term derived from low temperature heat capacity measurements. This paper investigates how such a model performs in both random and partially clustered vacancy systems. The heat capacity measurements were used to investigate the effect of singly (Nd or Sm) doped and co-doped (Nd and Sm) ceria, where simultaneous doping affects vacancy clustering and ionic conductivity. Comparison of calculated vacancy concentrations with sample stoichiometries showed that a vacancy concentration based on the linear term in the low temperature heat capacity is quantitative for near randomly distributed vacancies at low dopant concentration, but the prediction is low by approximately an order of magnitude when vacancies become clustered at higher dopant levels. This confirms that the linear term in the low-temperature heat capacity for non-metallic materials is a viable approach to estimate the vacancy concentration for randomly distributed vacancies which, in turn, can be used to distinguish between the random versus clustered vacancies.
PB  - Elsevier
T2  - Acta Materialia
T1  - Quantifying oxygen vacancies in neodymium and samarium doped ceria from heat capacity measurements
VL  - 188
SP  - 740
EP  - 744
DO  - 10.1016/j.actamat.2020.02.055
ER  - 

@article{
author = "Neilsen, Grace and Rosen, Peter and Dickson, Matthew and Popović, Marko and Schliesser, Jacob and Hansen, Lee and Navrotsky, Alexandra and Woodfield, Brian",
year = "2020",
abstract = "It has been previously reported in the literature that the vacancy concentration in a solid can be estimated using the linear term derived from low temperature heat capacity measurements. This paper investigates how such a model performs in both random and partially clustered vacancy systems. The heat capacity measurements were used to investigate the effect of singly (Nd or Sm) doped and co-doped (Nd and Sm) ceria, where simultaneous doping affects vacancy clustering and ionic conductivity. Comparison of calculated vacancy concentrations with sample stoichiometries showed that a vacancy concentration based on the linear term in the low temperature heat capacity is quantitative for near randomly distributed vacancies at low dopant concentration, but the prediction is low by approximately an order of magnitude when vacancies become clustered at higher dopant levels. This confirms that the linear term in the low-temperature heat capacity for non-metallic materials is a viable approach to estimate the vacancy concentration for randomly distributed vacancies which, in turn, can be used to distinguish between the random versus clustered vacancies.",
publisher = "Elsevier",
journal = "Acta Materialia",
title = "Quantifying oxygen vacancies in neodymium and samarium doped ceria from heat capacity measurements",
volume = "188",
pages = "740-744",
doi = "10.1016/j.actamat.2020.02.055"
}

Neilsen, G., Rosen, P., Dickson, M., Popović, M., Schliesser, J., Hansen, L., Navrotsky, A.,& Woodfield, B.. (2020). Quantifying oxygen vacancies in neodymium and samarium doped ceria from heat capacity measurements. in Acta Materialia
Elsevier., 188, 740-744.
https://doi.org/10.1016/j.actamat.2020.02.055

Neilsen G, Rosen P, Dickson M, Popović M, Schliesser J, Hansen L, Navrotsky A, Woodfield B. Quantifying oxygen vacancies in neodymium and samarium doped ceria from heat capacity measurements. in Acta Materialia. 2020;188:740-744.
doi:10.1016/j.actamat.2020.02.055 .

Neilsen, Grace, Rosen, Peter, Dickson, Matthew, Popović, Marko, Schliesser, Jacob, Hansen, Lee, Navrotsky, Alexandra, Woodfield, Brian, "Quantifying oxygen vacancies in neodymium and samarium doped ceria from heat capacity measurements" in Acta Materialia, 188 (2020):740-744,
https://doi.org/10.1016/j.actamat.2020.02.055 . .