168086 20260126155509.0 sideral 146853 ART-2015-146853 eng Kiirat, G. Decrease of Ca3Co4O9+δthermal conductivity by Yb-doping 2015 In this study, the effect of Yb-substitution on the structural, electrical and thermal transport properties of the Ca 3Co 4O 9 þ δ system has been investigated in the low temperature region (between 10 and 300 K). The resistivity of samples increases with raising the Yb-concentration in the system. All the samples show a metal-semiconductor transition below 85 K. In the analysis based on Strongly Correlated Fermi Liquid Model, an increased bandwidth and a reduced electronic correlation are found. It has also been found that the energy gap, E0, value also decreases with Yb substitution. The samples show positive thermoelectric power, indicating that dominant charge carriers are holes in all the samples. The thermoelectric power value decreases with Yb-substitution. From Mott equation, it is determined that the Fermi energy and hole concentration decrease in the Yb-susbtituted samples, compared to the undoped ones. Thermal conductivity, κ, is decreased in about 50% of the measured in undoped samples for the 0.01 and 0.03 Yb-doped samples at 300 K. Highest figure of merit, ZT, value is found to be 5.4 10 3 at 300 K for the unsubstituted sample and the ZT value decreases by the substitution. Access copy available to the general public Unrestricted info:eu-repo/grantAgreement/ES/DGA/T12 info:eu-repo/grantAgreement/ES/DGA/T87 info:eu-repo/grantAgreement/ES/MINECO-FEDER/MAT2013-46505-C3-1-R info:eu-repo/semantics/openAccess by-nc-nd https://creativecommons.org/licenses/by-nc-nd/4.0/deed.es 2.758 2015 MATERIALS SCIENCE, CERAMICS 3 / 27 = 0.111 2015 Q1 T1 0.823 2015 Ceramics and Composites 2015 Q1 Electronic, Optical and Magnetic Materials 2015 Q1 Surfaces, Coatings and Films 2015 Q1 Process Chemistry and Technology 2015 Q1 Materials Chemistry 2015 Q1 info:eu-repo/semantics/article info:eu-repo/semantics/acceptedVersion Aksan, M.A. Rasekh, Sh. (orcid)0000-0003-3466-9952 Madre, M.A. Universidad de Zaragoza (orcid)0000-0002-0794-3998 Diez, J.C. Universidad de Zaragoza (orcid)0000-0001-9995-6368 Sotelo, A. Universidad de Zaragoza (orcid)0000-0001-7056-0546 5001 065 Universidad de Zaragoza Dpto. Ciencia Tecnol.Mater.Fl. Área Cienc.Mater. Ingen.Metal. 41, 10 (2015), 12515-12528 Ceram. int. Ceramics International 0272-8842 1052427 http://zaguan.unizar.es/record/168086/files/texto_completo.pdf Postprint 1539017 http://zaguan.unizar.es/record/168086/files/texto_completo.jpg?subformat=icon icon Postprint oai:zaguan.unizar.es:168086 articulos driver 2026-01-26-14:50:10 ARTICLE