ChemInform Abstract: Crystal Structure, Characterization and Thermoelectric Properties of the Type-I Clathrate Ba8-ySryAl14Si32 (0.6 ≤ y ≤ 1.3) Prepared by Aluminum Flux.

ChemInform ◽  
2011 ◽  
Vol 42 (34) ◽  
pp. no-no
Author(s):  
John H. Roudebush ◽  
Eric S. Toberer ◽  
Haakon Hope ◽  
G. Jeffrey Snyder ◽  
Susan M. Kauzlarich
Keyword(s):  
Crystal Structure ◽  
Thermoelectric Properties ◽  
Structure Characterization ◽  
Type I

Crystal structure, characterization and thermoelectric properties of the type-I clathrate Ba8−ySryAl14Si32 (0.6≤y≤1.3) prepared by aluminum flux

2011 ◽  
Vol 184 (5) ◽  
pp. 1176-1185 ◽  
Author(s):  
John H. Roudebush ◽  
Eric S. Toberer ◽  
Håkon Hope ◽  
G. Jeffrey Snyder ◽  
Susan M. Kauzlarich
Keyword(s):  
Crystal Structure ◽  
Thermoelectric Properties ◽  
Structure Characterization ◽  
Type I

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.

scholarly journals Crystal structure and thermoelectric properties of the type-I clathrate compound Ba8Ge43 with an ordered arrangement of Ge vacancies

2006 ◽  
Vol 99 (3) ◽  
pp. 033513 ◽  
Author(s):  
Norihiko L. Okamoto ◽  
Min Wook Oh ◽  
Takumi Nishii ◽  
Katsushi Tanaka ◽  
Haruyuki Inui
Keyword(s):  
Crystal Structure ◽  
Thermoelectric Properties ◽  
Type I ◽  
Clathrate Compound

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

scholarly journals Structural and Thermoelectric Properties of Cu Substituted Type I Clathrates Ba8CuxSi~32−xGa~14

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 237 ◽  
Author(s):  
Yue Dong ◽  
Xueyong Ding ◽  
Xinlin Yan ◽  
Long Zhang ◽  
Tianhua Ju ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Electrical Resistivity ◽  
Thermoelectric Properties ◽  
Charge Carrier Concentration ◽  
Type I ◽  
X Ray Diffraction ◽  
Ring Plane ◽  
Principal Mechanism ◽  
X Ray ◽  
Cu Substitution

With an attempt to improve the thermoelectric properties of type I clathrates in the Ba-Ga-Si system, we introduce Cu into the framework of the crystal structure. Single crystals are prepared in Ga-flux and characterized by X-ray diffraction techniques and transport measurements for the structural and thermoelectric properties. Our composition analyses show that only a small amount of Cu is determined in the clathrates. The single crystal X-ray diffraction data refinements confirm that Ga atoms prefer the 6c and 24k sites and avoid the 16i sites in the crystal structure. The small amount of Cu affects the crystal structure by compressing the tetrakaidecahedral cage along the direction perpendicular to the six-atom-ring plane. This could be the reason for the high charge carrier concentration, and low electrical resistivity and Seebeck coefficient. We analyze the principal mechanism for our observation and conclude that the Cu substitution can adjust some subtle details of the structure, maintaining the Zintl rule in the type I clathrates.

Crystal structure of magnesium chromium vanadate Mg2CrV3O11, a member of the A2BV3O11 vanadate family

2007 ◽  
Vol 22 (3) ◽  
pp. 246-252 ◽  
Author(s):  
A. Worsztynowicz ◽  
S. M. Kaczmarek ◽  
W. Paszkowicz ◽  
R. Minikayev
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Ion Pairs ◽  
Exchange Constant ◽  
Type I ◽  
Type Ii ◽  
Paramagnetic Resonance ◽  
Interatomic Distances ◽  
Electron Paramagnetic ◽  
Full Occupancy

The crystal structure of recently discovered chromium (III) dimagnesium trivanadate (V) Mg2CrV3O11 was refined using the Rietveld method. The crystal system of Mg2CrV3O11 is triclinic with space group P1− (Mg1.7Zn0.3GaV3O11 type) and lattice parameters a=6.4057(1) Å, b=6.8111(1) Å, c=10.0640(2) Å, α=97.523(1)°, β=103.351(1)°, γ=101.750(1)°, and Z=2. The characteristic feature of compounds in the A2BV3O11 (A=Mg, Zn and B=Ga, Fe, Cr) family is a strong tendency to share the octahedral M(1) and M(2) sites by both divalent A and trivalent B atoms, and the bipyramidal M(3) sites occupied by divalent A ions. In the present refinement, the only constraint assuming full occupancy of the M(1), M(2), and M(3) sites leads to the following Cr/(Cr+Mg) ratios: 0.70(2) at M(1), 0.24(2) at M(2), and 0.03(2) at M(3). These occupancies are discussed and compared to those of isotypic compounds. The values of interatomic distances are found to be comparable with those reported by R. D. Shannon in 1976. Electron paramagnetic resonance has been also analyzed. Two absorption lines with g≈2.0 (type I) and g≈1.98 (type II) have been recorded in the EPR spectra, and attributed to V4+ ions and Cr3+–Cr3+ ion pairs, respectively. The exchange constant J between Cr3+ ions has been calculated.

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