1887
banner image
No data available.
Please log in to see this content.
You have no subscription access to this content.
No metrics data to plot.
The attempt to load metrics for this article has failed.
The attempt to plot a graph for these metrics has failed.
Crystal structure and thermoelectric properties of type-I clathrate compounds in the Ba–Ga–Ge system
Rent:
Rent this article for
USD
10.1063/1.2355443
/content/aip/journal/jap/100/7/10.1063/1.2355443
http://aip.metastore.ingenta.com/content/aip/journal/jap/100/7/10.1063/1.2355443

Figures

Image of FIG. 1.
FIG. 1.

SEM backscattered electron images of oil-quenched specimens with (a) and (c) and furnace-cooled specimens with (b) , (d) , (e) , (f) , (g) , and (h) .

Image of FIG. 2.
FIG. 2.

(a) X-ray powder diffraction patterns in the range from 3.5° to 9° for the oil-quenched specimen with and furnace-cooled specimens with , 6, 12, and 16. The pattern for the binary type-I clathrate compound is also shown for comparison. The solid arrows indicate superlattice reflections, while open and double arrows indicate reflections from Ge and type-III clathrate phases, respectively. (b) X-ray powder diffraction pattern in the range from 3.5° to 50° for the specimen with .

Image of FIG. 3.
FIG. 3.

Portions of the ternary phase diagram in the Ba–Ga–Ge system at . The broken line corresponding to compositions of type-I clathrate compounds formed without any Ge vacancies is also drawn. The open circles correspond to the nominal compositions of the specimens used.

Image of FIG. 4.
FIG. 4.

Lattice constant of the type-I clathrate compounds plotted as a function of Ga content. The Ga contents deduced from EDS analyses (Table I) were used in the plot.

Image of FIG. 5.
FIG. 5.

(a) Electrical resistivity, (b) Seebeck coefficient, and (c) thermal conductivity for the specimens with plotted as functions of temperature. The inset in (a) shows the values of electrical resistivity at plotted as a function of Ga content.

Image of FIG. 6.
FIG. 6.

Dimensionless figure of merit (ZT) for the specimens with plotted as a function of temperature.

Image of FIG. 7.
FIG. 7.

ADP at the Ba(2) site plotted as functions of (a) Ga content and (b) the average bond length between the Ba(2) atom and encapsulating atoms.

Image of FIG. 8.
FIG. 8.

Lattice thermal conductivity at room temperature plotted as functions of (a) Ga content and (b) ADP at the Ba(2) site.

Tables

Generic image for table
Table I.

Ga and Ge contents in the type-I clathrate compounds obtained by EDS analyses. In the analyses, the Ba sites are assumed to be fully occupied.

Generic image for table
Table II.

Results of Rietveld refinement for the type-I clathrate phase in the specimen with . The space group is and the lattice parameter is . The residual parameters and are 0.0256 and 0.0185, respectively.

Generic image for table
Table III.

Results of Rietveld refinement for the type-I clathrate phase in the specimens with . The space group is and atom positions are Ba(1) 0,0,0; Ba(2) ; ; ; and .

Generic image for table
Table IV.

Chemical compositions, number of Ge vacancies, and number of excess electrons per unit formula in the type-I clathrate compounds. The chemical compositions and number of Ge vacancies per unit formula were obtained from EDS and Rietveld analyses, while the number of excess electrons per unit formula was calculated based on the charge compensation concept.

Generic image for table
Table V.

Atomic bond lengths and numbers of the corresponding atomic bonds for the type-I clathrate phase in the specimen with . The symbols “prime” and “double prime” were used to differentiate crystallographycally equivalent sites with different bond lengths from each other.

Generic image for table
Table VI.

Atomic bond lengths and numbers of the corresponding atomic bonds for the normal type-I clathrate phase in the specimen with . The symbol “prime” was used to differentiate crystallographycally equivalent sites with different bond lengths from each other.

Loading

Article metrics loading...

/content/aip/journal/jap/100/7/10.1063/1.2355443
2006-10-03
2014-04-19
Loading

Full text loading...

This is a required field
Please enter a valid email address
752b84549af89a08dbdd7fdb8b9568b5 journal.articlezxybnytfddd
Scitation: Crystal structure and thermoelectric properties of type-I clathrate compounds in the Ba–Ga–Ge system
http://aip.metastore.ingenta.com/content/aip/journal/jap/100/7/10.1063/1.2355443
10.1063/1.2355443
SEARCH_EXPAND_ITEM