Thermoelectric properties and crystal structure of type-III clathrate compounds in the Ba–Al–Ge system

2007 ◽  
Vol 102 (3) ◽  
pp. 034510 ◽  
Author(s):  
Jung-Hwan Kim ◽  
Norihiko L. Okamoto ◽  
Kyosuke Kishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structure ◽  
Thermoelectric Properties ◽  
Type Iii ◽  
Clathrate Compounds

Crystal structure and thermoelectric properties of type-III clathrate compounds in the Ba–In–Ge system

2007 ◽  
Vol 102 (9) ◽  
pp. 094506 ◽  
Author(s):  
Jung-Hwan Kim ◽  
Norihiko L. Okamoto ◽  
Kyosuke Kishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structure ◽  
Thermoelectric Properties ◽  
Type Iii ◽  
Clathrate Compounds

Thermoelectric properties of Ba-Ge based Type-III Clathrate Compounds

2006 ◽  
Vol 980 ◽  
Author(s):  
Jung-Hwan Kim ◽  
Norihiko L. Okamoto ◽  
Kyosuke Kishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Seebeck Coefficient ◽  
Thermoelectric Properties ◽  
Lattice Thermal Conductivity ◽  
Type Iii ◽  
Clathrate Compounds ◽  
Coefficient Increase ◽  
Excess Electrons ◽  
Anisotropic Deformation

AbstractThe crystal structures and thermoelectric properties of Ba-Ge based type-III clathrate compounds in Ba-Al-Ge and Ba-In-Ge systems have been investigated as a function of Al and In content. The absolute values of electrical resistivity and Seebeck coefficient increase, while that of lattice thermal conductivity decreases with increasing Al and In content. The increase in electrical resistivity and Seebeck coefficient is discussed in terms of the number of the excess electrons deduced from the Zintl concept, on the other hand, the decrease in lattice thermal conductivity is discussed in terms of an anisotropic deformation of the open-dodecahedron cage encapsulating Ba atom. High ZT values of 0.74 and 0.87 are obtained at 780 and 580 °C for Ba24Al12Ge88 and Ba24In16Ge84, respectively.

Structural analysis and thermoelectric properties of Type-I clathrate compounds in the Ba-Ge-Ga system

2003 ◽  
Vol 793 ◽  
Author(s):  
Norihiko L. Okamoto ◽  
Takumi Nishii ◽  
Min Wook Oh ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structure ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Stoichiometric Composition ◽  
Binary Compound ◽  
Type I ◽  
Normal Type ◽  
Ternary Compounds ◽  
Clathrate Compounds ◽  
Ga Content

ABSTRACTThe crystal structure and thermoelectric properties of Type-I clathrate compounds in the Ba-Ge-Ga system (Ba8GaXGe46-X) have been investigated as a function of Ga content. While all ternary compounds containing more than 3 Ga exhibit a crystal structure of normal Type-I clathrates with the space group Pm 3 n, the binary compound possesses a composition Ba8Ge43, which is leaner in Ge than the stoichiometric composition, and has a crystal structure different from that of normal Type-I clathrates because of the ordering of Ge vacancies in 6c sites of the parent normal Type-I clathrate structure. The temperature dependence of electrical resistivity of binary Ba8Ge43 is of semiconductor while that for all the ternary compounds is metallic. The value of Seebeck coefficient increases with the increase in the Ga content. The value of dimensionless figure of merit (ZT) increases with the increase in the Ga content, exhibiting a high value of 0.76 at 700°C for Ba8Ga16Ge30.

ChemInform Abstract: Cationic Clathrate of Type-III Ge172-xPxTey(y ≈ 21.5, x ≈ 2y): Synthesis, Crystal Structure and Thermoelectric Properties.

ChemInform ◽  
2013 ◽  
Vol 44 (38) ◽  
pp. no-no
Author(s):  
Maria A. Kirsanova ◽  
Takao Mori ◽  
Satofumi Maruyama ◽  
Artem M. Abakumov ◽  
Gustaaf Van Tendeloo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermoelectric Properties ◽  
Type Iii

Crystal structure and atomic vibration of Ba-Ge based type-III clathrate compounds

2007 ◽  
Author(s):  
Jung-Hwan Kim ◽  
Norihiko L. Okamoto ◽  
Kyosuke Kishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structure ◽  
Atomic Vibration ◽  
Type Iii ◽  
Clathrate Compounds

Effects of Ga- and In-doping on the Thermoelectric Properties in Ba-Ge Clathrate Compounds

2004 ◽  
Vol 842 ◽  
Author(s):  
Norihiko L. Okamoto ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structure ◽  
Thermoelectric Properties ◽  
Figure Of Merit ◽  
Type I ◽  
Thermoelectric Figure Of Merit ◽  
Normal Type ◽  
Thermoelectric Figure ◽  
Clathrate Compounds ◽  
In Doping ◽  
Ga Content

ABSTRACTThe crystal structures and thermoelectric properties of Ba-Ge type-I clathrate compounds (Ba8GaXGe46-X and Ba8Ga16-YInYGe30) have been investigated as a function of Ga and In contents. Ba8GaXGe46-X alloys have a crystal structure that contains an ordered arrangement of Ge vacancies, forming a superstructure based on the normal type-I structure until X reaches 3, whereas they have the normal type-I structure when X exceeds 3. The dimensionless thermoelectric figure of merit (ZT) increases with the increase in the Ga content, exhibiting the highest value of 0.49 for Ba8Ga16Ge30. The power factor for Ba8Ga10In6Ge30 is 1.5 times that for Ba8Ga16Ge30 so that the In containing alloy exhibits a ZT value as high as 1.03 at 700°C.

scholarly journals Crystal structure and thermoelectric properties of type-I clathrate compounds in the Ba–Ga–Ge system

2006 ◽  
Vol 100 (7) ◽  
pp. 073504 ◽  
Author(s):  
Norihiko L. Okamoto ◽  
Kyosuke Kishida ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structure ◽  
Thermoelectric Properties ◽  
Type I ◽  
Clathrate Compounds

Cationic Clathrate of Type-III Ge172–xPxTey (y ≈ 21.5, x ≈ 2y): Synthesis, Crystal Structure and Thermoelectric Properties

2013 ◽  
Vol 52 (14) ◽  
pp. 8272-8279 ◽  
Author(s):  
Maria A. Kirsanova ◽  
Takao Mori ◽  
Satofumi Maruyama ◽  
Artem M. Abakumov ◽  
Gustaaf Van Tendeloo ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Thermoelectric Properties ◽  
Type Iii

Effect of Ga-doping on the Thermoelectric Properties of Ba-Ge Type-III Clathrate Compounds

2005 ◽  
Vol 886 ◽  
Author(s):  
Jung-Hwan Kim ◽  
Norihiko L. Okamoto ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Thermal Conductivity ◽  
Electrical Resistivity ◽  
Thermoelectric Properties ◽  
Lattice Thermal Conductivity ◽  
Type Iii ◽  
Clathrate Compounds ◽  
Coefficient Increase ◽  
Ga Doping ◽  
Very High ◽  
Ga Content

ABSTRACTEffect of Ga addition on the thermoelectric properties of Ba-Ge type-III clathrate has been investigated as a function of Ga content and temperature. The substitution of Ga atom for Ge atom leads to the decrease of carrier (electron) concentration. Electrical conduction is of n-type for all clathrate compounds investigated and the values of electrical resistivity and Seebeck coefficient increase with the increase in the Ga content and in temperature. Both electronic and lattice thermal conductivity decrease with the increase in the Ga content because of the decreased carrier concentration and the increased extent of the rattling motion of Ba atoms encapsulated in open-dodecahedron, respectively. A very high ZT value of 1.25 is obtained at 670 °C for Ba24Ga15Ge85.

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