Role of phonon scattering by elastic strain field in thermoelectric Sr1−xYxTiO3−δ

Handle URI:
http://hdl.handle.net/10754/552154
Title:
Role of phonon scattering by elastic strain field in thermoelectric Sr1−xYxTiO3−δ
Authors:
Bhattacharya, S.; Mehdizadeh Dehkordi, A.; Tennakoon, S.; Adebisi, R.; Gladden, J. R.; Darroudi, T.; Alshareef, Husam N. ( 0000-0001-5029-2142 ) ; Tritt, T. M.
Abstract:
Perovskite-type SrTiO3-δ ceramics are multifunctional materials with significant potential as n-type thermoelectric (TE) materials. The electronic and thermal transport properties of spark plasma sintered polycrystalline Sr1-xYxTiO3-δ (x=0.05, 0.075, 0.1) ceramics are systematically investigated from (15-800) K. The Sr0.9Y0.1TiO3-δ simultaneously exhibits a large Seebeck coefficient, α>-80μV/K and moderately high electrical resistivity, ρ∼0.8mΩ-cm at a carrier concentration of ∼1021cm-3 at 300K resulting in a high TE power factor defined herein as (α2σT)∼0.84W/m-K at 760K. Despite the similar atomic masses of Sr (87.6g/mol) and Y (88.9g/mol), the lattice thermal conductivity (κL) of Sr1-xY xTiO3-δ is significantly reduced with increased Y-doping, owing to the smaller ionic radii of Y3+ (∼1.23Å, coordination number 12) compared to Sr2+ (∼1.44Å, coordination number 12) ions. In order to understand the thermal conductivity reduction mechanism, the κL in the Sr1-xY xTiO3-δ series are phenomenologically modeled with a modified Callaway's equation from 30-600K. Phonon scattering by elastic strain field due to ionic radii mismatch is found to be the prominent scattering mechanism in reducing κL of these materials. In addition, the effect of Y-doping on the elastic moduli of Sr1-xY xTiO3-δ (x=0, 0.1) is investigated using resonant ultrasound spectroscopy, which exhibits an anomaly in x=0.1 in the temperature range 300-600K. As a result, the phonon mean free path is found to be further reduced in the Sr0.9Y0.1TiO3-δ compared to that of SrTiO3-δ, resulting in a considerably low thermal conductivity κ∼2.7W/m-K at 760K. Finally, we report a thermoelectric figure of merit (ZT)∼0.3 at 760K in the Sr0.9Y 0.1TiO3-δ, the highest ZT value reported in the Y-doped SrTiO3 ceramics thus far. © 2014 AIP Publishing LLC.
KAUST Department:
Materials Science and Engineering Program
Citation:
Role of phonon scattering by elastic strain field in thermoelectric Sr1−xYxTiO3−δ 2014, 115 (22):223712 Journal of Applied Physics
Publisher:
AIP Publishing
Journal:
Journal of Applied Physics
Issue Date:
12-Jun-2014
DOI:
10.1063/1.4882377
Type:
Article
ISSN:
0021-8979; 1089-7550
Additional Links:
http://scitation.aip.org/content/aip/journal/jap/115/22/10.1063/1.4882377
Appears in Collections:
Articles; Materials Science and Engineering Program

Full metadata record

DC FieldValue Language
dc.contributor.authorBhattacharya, S.en
dc.contributor.authorMehdizadeh Dehkordi, A.en
dc.contributor.authorTennakoon, S.en
dc.contributor.authorAdebisi, R.en
dc.contributor.authorGladden, J. R.en
dc.contributor.authorDarroudi, T.en
dc.contributor.authorAlshareef, Husam N.en
dc.contributor.authorTritt, T. M.en
dc.date.accessioned2015-05-04T16:30:19Zen
dc.date.available2015-05-04T16:30:19Zen
dc.date.issued2014-06-12en
dc.identifier.citationRole of phonon scattering by elastic strain field in thermoelectric Sr1−xYxTiO3−δ 2014, 115 (22):223712 Journal of Applied Physicsen
dc.identifier.issn0021-8979en
dc.identifier.issn1089-7550en
dc.identifier.doi10.1063/1.4882377en
dc.identifier.urihttp://hdl.handle.net/10754/552154en
dc.description.abstractPerovskite-type SrTiO3-δ ceramics are multifunctional materials with significant potential as n-type thermoelectric (TE) materials. The electronic and thermal transport properties of spark plasma sintered polycrystalline Sr1-xYxTiO3-δ (x=0.05, 0.075, 0.1) ceramics are systematically investigated from (15-800) K. The Sr0.9Y0.1TiO3-δ simultaneously exhibits a large Seebeck coefficient, α>-80μV/K and moderately high electrical resistivity, ρ∼0.8mΩ-cm at a carrier concentration of ∼1021cm-3 at 300K resulting in a high TE power factor defined herein as (α2σT)∼0.84W/m-K at 760K. Despite the similar atomic masses of Sr (87.6g/mol) and Y (88.9g/mol), the lattice thermal conductivity (κL) of Sr1-xY xTiO3-δ is significantly reduced with increased Y-doping, owing to the smaller ionic radii of Y3+ (∼1.23Å, coordination number 12) compared to Sr2+ (∼1.44Å, coordination number 12) ions. In order to understand the thermal conductivity reduction mechanism, the κL in the Sr1-xY xTiO3-δ series are phenomenologically modeled with a modified Callaway's equation from 30-600K. Phonon scattering by elastic strain field due to ionic radii mismatch is found to be the prominent scattering mechanism in reducing κL of these materials. In addition, the effect of Y-doping on the elastic moduli of Sr1-xY xTiO3-δ (x=0, 0.1) is investigated using resonant ultrasound spectroscopy, which exhibits an anomaly in x=0.1 in the temperature range 300-600K. As a result, the phonon mean free path is found to be further reduced in the Sr0.9Y0.1TiO3-δ compared to that of SrTiO3-δ, resulting in a considerably low thermal conductivity κ∼2.7W/m-K at 760K. Finally, we report a thermoelectric figure of merit (ZT)∼0.3 at 760K in the Sr0.9Y 0.1TiO3-δ, the highest ZT value reported in the Y-doped SrTiO3 ceramics thus far. © 2014 AIP Publishing LLC.en
dc.publisherAIP Publishingen
dc.relation.urlhttp://scitation.aip.org/content/aip/journal/jap/115/22/10.1063/1.4882377en
dc.rightsArchived with thanks to Journal of Applied Physicsen
dc.titleRole of phonon scattering by elastic strain field in thermoelectric Sr1−xYxTiO3−δen
dc.typeArticleen
dc.contributor.departmentMaterials Science and Engineering Programen
dc.identifier.journalJournal of Applied Physicsen
dc.eprint.versionPublisher's Version/PDFen
dc.contributor.institutionDepartment of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634, USAen
dc.contributor.institutionDepartment of Materials Science and Engineering, Clemson University, Clemson, South Carolina 29634, USAen
dc.contributor.institutionDepartment of Physics and National Center for Physical Acoustics, University of Mississippi, University, Mississippi 38677, USAen
dc.contributor.institutionDepartment of Physics and National Center for Physical Acoustics, University of Mississippi, University, Mississippi 38677, USAen
dc.contributor.institutionDepartment of Physics and National Center for Physical Acoustics, University of Mississippi, University, Mississippi 38677, USAen
dc.contributor.institutionElectron Microscope Facility, Clemson Research Park, Clemson University, Clemson, South Carolina 29625, USAen
dc.contributor.institutionDepartment of Physics and Astronomy, Clemson University, Clemson, South Carolina 29634, USAen
kaust.authorAlshareef, Husam N.en
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