Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519946
I. Terasaki
The layered cobalt oxides having the CdI2-type hexagonal CoO/sub 2/ layer exhibit good thermoelectric properties especially at high temperatures. The layered structure works quite well in this system. However, such fortunate situations rarely occur in the layered 3d transition-metal oxides, where the carrier is strongly coupled with phonons to form a polaron. In contrast, in the layered 4d transition-metal oxides we did not find any trance of polaron conduction. In this article, we will make a brief review of the thermoelectric properties of various layered transition-metal oxides.
{"title":"Thermoelectric materials in layered transition-metal oxides","authors":"I. Terasaki","doi":"10.1109/ICT.2005.1519946","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519946","url":null,"abstract":"The layered cobalt oxides having the CdI2-type hexagonal CoO/sub 2/ layer exhibit good thermoelectric properties especially at high temperatures. The layered structure works quite well in this system. However, such fortunate situations rarely occur in the layered 3d transition-metal oxides, where the carrier is strongly coupled with phonons to form a polaron. In contrast, in the layered 4d transition-metal oxides we did not find any trance of polaron conduction. In this article, we will make a brief review of the thermoelectric properties of various layered transition-metal oxides.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132581906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519949
K. Kurosaki, A. Kosuga, K. Goto, H. Muta, S. Yamanaka
We have studied the thermoelectric properties Ag/sub 9/TlTe/sub 5/ and AgTlTe. The thallium compounds have extremely low thermal conductivities around 0.25 Wm/sup -1/K/sup -1/ from room temperature to about 700 K. The thallium compounds indicate very high ZT values; especially the highest ZT value of Ag/sub 9/TlTe/sub 5/ is 1.23 obtained at 700 K. Ag/sub 9/TlTe/sub 5/ is a unique material combining extremely low thermal conductivity and relatively low electrical resistivity.
{"title":"Ag/sub 9/TlTe/sub 5/ and AgTlTe: high ZT materials with extremely low thermal conductivity","authors":"K. Kurosaki, A. Kosuga, K. Goto, H. Muta, S. Yamanaka","doi":"10.1109/ICT.2005.1519949","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519949","url":null,"abstract":"We have studied the thermoelectric properties Ag/sub 9/TlTe/sub 5/ and AgTlTe. The thallium compounds have extremely low thermal conductivities around 0.25 Wm/sup -1/K/sup -1/ from room temperature to about 700 K. The thallium compounds indicate very high ZT values; especially the highest ZT value of Ag/sub 9/TlTe/sub 5/ is 1.23 obtained at 700 K. Ag/sub 9/TlTe/sub 5/ is a unique material combining extremely low thermal conductivity and relatively low electrical resistivity.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"42 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116468197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519919
A. Bentien, G. Madsen, S. Johnsen, B. Iversen
FeSb/sub 2/ is a diamagnetic semiconductor where the Fe 3d levels are located just below the band gap. A series of systematically Sn substituted FeSb/sub 2-x/Sn/sub x/ samples with x = 0-0.15 has been synthesized and we explore the thermoelectric properties of these samples as the Fermi level is shifted down into the region of the Fe 3d levels.
{"title":"Thermoelectric properties of hole doped FeSb/sub 2/","authors":"A. Bentien, G. Madsen, S. Johnsen, B. Iversen","doi":"10.1109/ICT.2005.1519919","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519919","url":null,"abstract":"FeSb/sub 2/ is a diamagnetic semiconductor where the Fe 3d levels are located just below the band gap. A series of systematically Sn substituted FeSb/sub 2-x/Sn/sub x/ samples with x = 0-0.15 has been synthesized and we explore the thermoelectric properties of these samples as the Fermi level is shifted down into the region of the Fe 3d levels.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"48 1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116805689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519957
S. Bhattacharya, Malcolm Skove, M. Russell, T. Tritt, Y. Xia, V. Ponnambalam, J. Poon, N. Thadhani
Thermal conductivity of two series of Ti-based half-Heusler alloys have been investigated and compared. A significant reduction in the lattice thermal conductivity (/spl kappa//sub L/) in Ti/sub 1-y/Zr/sub y/NiSn/sub 0.95/Sb/sub 0.05/ via mass fluctuation scattering (y>20%) is observed. However, small amounts of Sb (x/spl les/5%) in TiNiSn/sub 1-x/Sb/sub x/ do not yield similar results. A non-systematic increase in /spl kappa//sub L/ in the TiNiSn/sub 1-x/Sb/sub x/ series was observed, even with the amounts (x/spl les/5%) of Sb-doping. Extensive investigations of the grain structure in these materials show that there is a direct correlation between /spl kappa//sub L/ and the average grain size in these materials. These results are in good agreement with the theoretical predictions of Goldsmid et al. Theoretical calculations relating to the phonon mean free path in both the series of compounds would also be presented and discussed.
{"title":"Grain structure and thermal transport properties of TiNiSn/sub 1-x/Sb/sub x/ and Ti/sub 1-y/Zr/sub y/NiSn/sub 0.95/Sb/sub 0.05/ half-Heusler alloys","authors":"S. Bhattacharya, Malcolm Skove, M. Russell, T. Tritt, Y. Xia, V. Ponnambalam, J. Poon, N. Thadhani","doi":"10.1109/ICT.2005.1519957","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519957","url":null,"abstract":"Thermal conductivity of two series of Ti-based half-Heusler alloys have been investigated and compared. A significant reduction in the lattice thermal conductivity (/spl kappa//sub L/) in Ti/sub 1-y/Zr/sub y/NiSn/sub 0.95/Sb/sub 0.05/ via mass fluctuation scattering (y>20%) is observed. However, small amounts of Sb (x/spl les/5%) in TiNiSn/sub 1-x/Sb/sub x/ do not yield similar results. A non-systematic increase in /spl kappa//sub L/ in the TiNiSn/sub 1-x/Sb/sub x/ series was observed, even with the amounts (x/spl les/5%) of Sb-doping. Extensive investigations of the grain structure in these materials show that there is a direct correlation between /spl kappa//sub L/ and the average grain size in these materials. These results are in good agreement with the theoretical predictions of Goldsmid et al. Theoretical calculations relating to the phonon mean free path in both the series of compounds would also be presented and discussed.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133940151","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519971
D. Vasilevskiy, P. Fréchette, S. Turenne, R. Masut
The use of (Bi/sub 1-x/Sb/sub x/)/sub 2/(Te/sub 1-y/Se/sub y/)/sub 3/ solid solution alloys instead of the Bi/sub 2/Te/sub 3/ binary compound allows a significant increase of its thermoelectric performance. This improvement is mainly related to the reduction of thermal conductivity of the crystal lattice due to increased phonon scattering obtained from the alloying effect. However the optimum amount of Sb and Se resulting in higher alloy performance remains uncertain. Moreover, it is not clear if the reduction of mobility of free charge carriers in alloys containing large amounts of Sb and Se is the only cause of thermoelectric performance degradation of such alloys. Other phenomena have been suggested to explain this behavior. In this research project, a series of quaternary alloys of n-type (Bi/sub 1-x/Sb/sub x/)/sub 2/(Te/sub 1-y/Se/sub y/)/sub 3/ have been characterized with Sb and Se content varying from 0 to 10%. The specimens were produced by mechanical alloying of powders and hot extrusion. The thermoelectric properties have been studied in the temperature range from 230 to 350 K. The mobility and concentration of charge carriers were evaluated as a function of temperature from 15 to 300 K. The results indicate that, for quaternary alloys in the higher end of the concentrations of Se and Sb studied here, the hypothesis of charge carrier mobility degradation due only to alloying effect is not sufficient to explain the data. We will discuss the effect of additional generation of defect complexes for these cases.
{"title":"Thermoelectric properties and transport phenomena in (Bi/sub 1-x/Sb/sub x/)/sub 2/(Te/sub 1-y/Se/sub y/)/sub 3/ quaternary n-type alloys produced by powder metallurgy and extrusion","authors":"D. Vasilevskiy, P. Fréchette, S. Turenne, R. Masut","doi":"10.1109/ICT.2005.1519971","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519971","url":null,"abstract":"The use of (Bi/sub 1-x/Sb/sub x/)/sub 2/(Te/sub 1-y/Se/sub y/)/sub 3/ solid solution alloys instead of the Bi/sub 2/Te/sub 3/ binary compound allows a significant increase of its thermoelectric performance. This improvement is mainly related to the reduction of thermal conductivity of the crystal lattice due to increased phonon scattering obtained from the alloying effect. However the optimum amount of Sb and Se resulting in higher alloy performance remains uncertain. Moreover, it is not clear if the reduction of mobility of free charge carriers in alloys containing large amounts of Sb and Se is the only cause of thermoelectric performance degradation of such alloys. Other phenomena have been suggested to explain this behavior. In this research project, a series of quaternary alloys of n-type (Bi/sub 1-x/Sb/sub x/)/sub 2/(Te/sub 1-y/Se/sub y/)/sub 3/ have been characterized with Sb and Se content varying from 0 to 10%. The specimens were produced by mechanical alloying of powders and hot extrusion. The thermoelectric properties have been studied in the temperature range from 230 to 350 K. The mobility and concentration of charge carriers were evaluated as a function of temperature from 15 to 300 K. The results indicate that, for quaternary alloys in the higher end of the concentrations of Se and Sb studied here, the hypothesis of charge carrier mobility degradation due only to alloying effect is not sufficient to explain the data. We will discuss the effect of additional generation of defect complexes for these cases.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"833 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116146684","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519915
K. Fukui, M. Nakamori, Y. Okamoto, Y. Inoue, J. Morimoto
In this paper, we report the recrystallization process of Si-Ge-Au amorphous thin film with extremely large thermoelectric power that was prepared in ultra high vacuum. We observed the morphology of samples by using FE-SEM and FE-TEM. We found that the power factor increased at near room temperature for high Au concentration samples. But after several annealing cycles, segregations were observed on high Au concentration samples. The diameter reached 30 /spl mu/m at maximum on 300 nm thickness thin film. These segregations were two types. One type was Au segregation and the other was Si-Ge segregation.
{"title":"Thermoelectric properties and morphology of Si-Ge-Au amorphous thin films with superior performance at near room temperature","authors":"K. Fukui, M. Nakamori, Y. Okamoto, Y. Inoue, J. Morimoto","doi":"10.1109/ICT.2005.1519915","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519915","url":null,"abstract":"In this paper, we report the recrystallization process of Si-Ge-Au amorphous thin film with extremely large thermoelectric power that was prepared in ultra high vacuum. We observed the morphology of samples by using FE-SEM and FE-TEM. We found that the power factor increased at near room temperature for high Au concentration samples. But after several annealing cycles, segregations were observed on high Au concentration samples. The diameter reached 30 /spl mu/m at maximum on 300 nm thickness thin film. These segregations were two types. One type was Au segregation and the other was Si-Ge segregation.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122246530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519997
Shui-Qing Yu, Jiang-Bo Wang, D. Ding, S. Johnson, Yong-Hang Zhang
Vibration-free solid-state optical coolers are promising candidates to replace mechanical Stirling coolers in many applications, especially in satellites and other space based systems. Among the many possible approaches, electroluminescence refrigeration using light emitting diodes (LEDs) is a highly desirable approach since LEDs are easy to integrate with electronic and optical devices to provide local cooling. Since electroluminescence refrigeration in LEDs involves both thermoelectric (TE) and optical processes, the interplay between these effects needs to be understood. In this paper, the study of electroluminescence refrigeration involving TE cooling effects in LEDs is presented. Unlike conventional TE coolers, which only provide heat transfer, electroluminescence coolers can achieve net cooling.
{"title":"Interplay of thermoelectric cooling and electroluminescence refrigeration in LEDs","authors":"Shui-Qing Yu, Jiang-Bo Wang, D. Ding, S. Johnson, Yong-Hang Zhang","doi":"10.1109/ICT.2005.1519997","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519997","url":null,"abstract":"Vibration-free solid-state optical coolers are promising candidates to replace mechanical Stirling coolers in many applications, especially in satellites and other space based systems. Among the many possible approaches, electroluminescence refrigeration using light emitting diodes (LEDs) is a highly desirable approach since LEDs are easy to integrate with electronic and optical devices to provide local cooling. Since electroluminescence refrigeration in LEDs involves both thermoelectric (TE) and optical processes, the interplay between these effects needs to be understood. In this paper, the study of electroluminescence refrigeration involving TE cooling effects in LEDs is presented. Unlike conventional TE coolers, which only provide heat transfer, electroluminescence coolers can achieve net cooling.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125428556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1519910
T. Kajikawa, M. Ozaki, K. Yamaguchi, H. Obara
The Japanese National Project "The Development for Advanced Thermoelectric Conversion Systems" supported by the New Energy and Industrial Technology Development Organization (NEDO) was started in FY2002 to be completed in FY2006.The final goal of the thermoelectric modules is to establish 15% in energy conversion efficiency with temperature difference of 550 K. Moreover, thermoelectric conversion systems technologies for high temperature waste heat to be applied to electric heating furnaces and diesel engines, as well as those for lower temperature one to be applied to projector lamps and large-scale electric transformers are being established for the realization of practical systems. By the end of 2004, the interim goal of the thermoelectric modules (12% in efficiency) and system technologies has already been cleared. The progress by the end of FY2004 and future prospects of the project are introduced.
{"title":"Progress of development for advanced thermoelectric conversion systems","authors":"T. Kajikawa, M. Ozaki, K. Yamaguchi, H. Obara","doi":"10.1109/ICT.2005.1519910","DOIUrl":"https://doi.org/10.1109/ICT.2005.1519910","url":null,"abstract":"The Japanese National Project \"The Development for Advanced Thermoelectric Conversion Systems\" supported by the New Energy and Industrial Technology Development Organization (NEDO) was started in FY2002 to be completed in FY2006.The final goal of the thermoelectric modules is to establish 15% in energy conversion efficiency with temperature difference of 550 K. Moreover, thermoelectric conversion systems technologies for high temperature waste heat to be applied to electric heating furnaces and diesel engines, as well as those for lower temperature one to be applied to projector lamps and large-scale electric transformers are being established for the realization of practical systems. By the end of 2004, the interim goal of the thermoelectric modules (12% in efficiency) and system technologies has already been cleared. The progress by the end of FY2004 and future prospects of the project are introduced.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129449204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1109/ICT.2005.1520000
J. Posthill, A. Reddy, E. Siivola, G. Krueger, M. Mantini, P. Thomas, R. Venkatasubramanian, F. Ochoa, P. Ronney
RTI is currently developing cascade and segmented thermoelectric (TE) power modules to achieve a thermal-to-electric efficiency target of 20%. In this context, we have achieved significant power levels with advanced bulk SiGe TE modules developed individually. Power levels over 1 W/sub e/ per module - with 11 W/sub e/ demonstrated by using 10 modules - now make a new thermoelectrics-based man-portable power supply potentially very attractive. These new modules are able to operate at high temperatures (>700/spl deg/C) and are thereby able to effectively utilize the temperature from direct combustion of any fuel such as butane, propane, natural gas, diesel or other logistics fuels. Combining: (1) these high-temperature SiGe TE modules with (2) a combustor with (3) a lightweight heat exchanger could enable TE to address man-portable off-grid requirements for fueled power sources.
{"title":"Portable power sources using combustion of butane and thermoelectrics","authors":"J. Posthill, A. Reddy, E. Siivola, G. Krueger, M. Mantini, P. Thomas, R. Venkatasubramanian, F. Ochoa, P. Ronney","doi":"10.1109/ICT.2005.1520000","DOIUrl":"https://doi.org/10.1109/ICT.2005.1520000","url":null,"abstract":"RTI is currently developing cascade and segmented thermoelectric (TE) power modules to achieve a thermal-to-electric efficiency target of 20%. In this context, we have achieved significant power levels with advanced bulk SiGe TE modules developed individually. Power levels over 1 W/sub e/ per module - with 11 W/sub e/ demonstrated by using 10 modules - now make a new thermoelectrics-based man-portable power supply potentially very attractive. These new modules are able to operate at high temperatures (>700/spl deg/C) and are thereby able to effectively utilize the temperature from direct combustion of any fuel such as butane, propane, natural gas, diesel or other logistics fuels. Combining: (1) these high-temperature SiGe TE modules with (2) a combustor with (3) a lightweight heat exchanger could enable TE to address man-portable off-grid requirements for fueled power sources.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121004601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2005-06-19DOI: 10.1002/9781118144121.CH34
A. Sakai, T. Kanno, S. Yotsuhashi, A. Odagawa, H. Adachi
We have investigated the control of crystal orientation in misfit layered cobaltite A/sub 3/Co/sub 4/O/sub 9/ (A=Ca, Sr) thin films and succeeded in growing epitaxial films with c-axis orientation perpendicular and parallel to the substrate surface by rf-planar magnetron sputtering. Anisotropic transport properties (parallel to the CoO/sub 2/ layers (/spl par/) and perpendicular to the CoO/sub 2/ layers (/spl perp/)) were measured using the epitaxial films with c-axis parallel to the film plane. The resistivity for Sr/sub 3/Co/sub 4/O/sub 9/ parallel to the CoO/sub 2/ layers (/spl rho//sub /spl par//) is about 2.5 m/spl Omega/ cm at room temperature while that perpendicular to the CoO/sub 2/ layers (/spl rho//sub /spl perp//) is about 150 m/spl Omega/ cm. Sr/sub 3/Co/sub 4/O/sub 9/ has lower parallel and perpendicular resistivity than Ca/sub 3/Co/sub 4/O/sub 9/. As for thermoelectric properties of Sr/sub 3/Co/sub 4/O/sub 9/, Seebeck coefficient parallel to the CoO/sub 2/ layers (S/sub /spl par//) is 90 /spl mu/V/K and that perpendicular to the CoO/sub 2/ layers (S/sub /spl perp//) is 30 /spl mu/V/K at room temperature. The power factor parallel to the CoO/sub 2/ layers is calculated to be 3/spl times/10/sup -4/ W/mK/sup 2/, about two times higher than that for Ca/sub 3/Co/sub 4/O/sub 9/. The anisotropic value of resistivity for Ca/sub 3/Co/sub 4/O/sub 9/ and Sr/sub 3/Co/sub 4/O/sub 9/ is about 40 and 60, respectively, and that of Seebeck Coefficient is similarly about 3.
{"title":"Preparation and anisotropic thermoelectric properties in misfit cobaltite thin films","authors":"A. Sakai, T. Kanno, S. Yotsuhashi, A. Odagawa, H. Adachi","doi":"10.1002/9781118144121.CH34","DOIUrl":"https://doi.org/10.1002/9781118144121.CH34","url":null,"abstract":"We have investigated the control of crystal orientation in misfit layered cobaltite A/sub 3/Co/sub 4/O/sub 9/ (A=Ca, Sr) thin films and succeeded in growing epitaxial films with c-axis orientation perpendicular and parallel to the substrate surface by rf-planar magnetron sputtering. Anisotropic transport properties (parallel to the CoO/sub 2/ layers (/spl par/) and perpendicular to the CoO/sub 2/ layers (/spl perp/)) were measured using the epitaxial films with c-axis parallel to the film plane. The resistivity for Sr/sub 3/Co/sub 4/O/sub 9/ parallel to the CoO/sub 2/ layers (/spl rho//sub /spl par//) is about 2.5 m/spl Omega/ cm at room temperature while that perpendicular to the CoO/sub 2/ layers (/spl rho//sub /spl perp//) is about 150 m/spl Omega/ cm. Sr/sub 3/Co/sub 4/O/sub 9/ has lower parallel and perpendicular resistivity than Ca/sub 3/Co/sub 4/O/sub 9/. As for thermoelectric properties of Sr/sub 3/Co/sub 4/O/sub 9/, Seebeck coefficient parallel to the CoO/sub 2/ layers (S/sub /spl par//) is 90 /spl mu/V/K and that perpendicular to the CoO/sub 2/ layers (S/sub /spl perp//) is 30 /spl mu/V/K at room temperature. The power factor parallel to the CoO/sub 2/ layers is calculated to be 3/spl times/10/sup -4/ W/mK/sup 2/, about two times higher than that for Ca/sub 3/Co/sub 4/O/sub 9/. The anisotropic value of resistivity for Ca/sub 3/Co/sub 4/O/sub 9/ and Sr/sub 3/Co/sub 4/O/sub 9/ is about 40 and 60, respectively, and that of Seebeck Coefficient is similarly about 3.","PeriodicalId":422400,"journal":{"name":"ICT 2005. 24th International Conference on Thermoelectrics, 2005.","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2005-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121266386","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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