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Your search keyword '"Saravanan, K. Venkata"' showing total 2 results
Start Over Author "Saravanan, K. Venkata" Topic electrical conductivity
2 results on '"Saravanan, K. Venkata"'

1. A Study on the Effects of La/Sm Codoping on the Structural and High Temperature Thermoelectric Properties of n‐Type CaMnO3−δ Perovskite.

Author

Vijay, Ammu, Prasanth S, Charan, Jose, Roshan, P, Vineetha, and Saravanan K, Venkata

Abstract

Oxide thermoelectric ceramics attract extensive research interest due to their excellent thermal stability, non‐toxicity, cost‐effectiveness, and earth‐abundant constituent elements. In the present work, the authors study the effect of lanthanum (La) and samarium (Sm) co‐doping on the structural, microstructural, and thermoelectric properties of CaMnO3 ceramics. The X‐ray diffraction (XRD) studies show an increase in unit cell volume with an increase in Sm concentration. A shift in Raman modes is observed, confirming distortions in MnO6 octahedra with the substitution of rare‐earth elements. The co‐doping strategy leads to a two‐order increment in electrical conductivity and reduction in thermopower as expected due to the increase in Mn3+ and charge carrier concentration. The highest electrical conductivity value attained is ≈200 S cm−1 at around 570 K for La0.025Sm0.1Ca0.875MnO3. The maximum value of thermoelectric power factor achieved is 194 μW m–1 K–2, which is two orders higher than that of the undoped CaMnO3. [ABSTRACT FROM AUTHOR]

Published
2022
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2. Abnormal Grain Growth as a Method To Enhance the Thermoelectric Performance of Nb-Doped Strontium Titanate Ceramics

Author

Resende, João, Elisabete Costa, Maria, Tkach, Alexander, Resende, Joao, Saravanan, K. Venkata, Costa, Maria Elisabete, Díaz-Chao, Pablo, Guilmeau, Emmanuel, Okhay, Olena, Vilarinho, Paula, Laboratoire des matériaux et du génie physique (LMGP ), Institut National Polytechnique de Grenoble (INPG)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Center for Research in Ceramic and Composite Materials (CICECO), Universidade de Aveiro, Periyar University, Laboratoire de cristallographie et sciences des matériaux (CRISMAT), École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Matériaux Avancés (IRMA), Normandie Université (NU)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Institut national des sciences appliquées Rouen Normandie (INSA Rouen Normandie), Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Rouen Normandie (UNIROUEN), and Institut National des Sciences Appliquées (INSA)-Normandie Université (NU)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Ceramics, Materials science, General Chemical Engineering, Donor doping, 02 engineering and technology, Abnormal grain growth, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Thermoelectric figure of merit, chemistry.chemical_compound, Submicrometer particles, Thermoelectric effect, Perovskite oxide electroceramics, Electrical conductivity, [CHIM.CRIS]Chemical Sciences/Cristallography, Environmental Chemistry, Ceramic, Composite material, Two-step sintering, Granular materials, Microstructure engineering, Renewable Energy, Sustainability and the Environment, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Thermoelectric materials, 0104 chemical sciences, Nb doped, chemistry, Thermal conductivity, visual_art, visual_art.visual_art_medium, Strontium titanate, Particle, Grain, 0210 nano-technology
Abstract

International audience; Driven by the need for high-temperature n-type thermoelectrics for energy-harvesting sectors, SrTi0.8Nb0.2O3±δ ceramics are prepared here from powders with average particle sizes of 270 and 800 nm by the conventional sintering in air at 1450 °C and further in H2/N2 at 1400 °C. In contrast to coarse particle powders, the use of fine particle powders under these conditions leads to abnormal grain growth and thereby bimodal grain size distribution in SrTi0.8Nb0.2O3±δ ceramics. As a result, a 3-fold increase in the thermoelectric figure of merit to 0.36 at 970 K is achieved, thus establishing the record value for bulk Nb-doped strontium titanate up to this temperature.

Published
2018
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