Single crystals thermopower

Structure calculations give a change-transfer value of 0.8. This value is in agreement with thermopower measurements. Raman spectroscopy studies performed on single crystals also confirm the fractional charge of the TTF units the Vc=c central bond of TTF appears at 1435 cm . From the study performed by Bozio et this frequency... 

Electrical conductivity and thermopower measurements on single crystals of t(NHs) tCk (MGS) and (TTF) NiS C H (TTF = tetrathiafulvalene) illustrate the application of electrical property measurements to the study of intermolecular interactions and electronic structure in planar metal complex systems. MGS is an anisotropic, p-type semiconductor conductivity along the metal-chain direction ohm ... 

The predictions OS.Sgi of the correct temperature dependence of the resistivity and the correct signs for both the Hall and thermopower tensors is a remarkable accomplishment for the band structure approaches. The discrepancies in the magnitudes of the calculated transport coefficients compared with experiMnt seem to us relatively minor. We therefore wish to oppose strongly the view suggested by some that band theory is completely irrelevant. It is very important that accurate single crystal measurements on these and other materials be performed to stimulate further theoretical progress. 

One of the unique properties the Si- and Ge-containing MAX phases is their small and temperature independent Seebeck coefficients [86, 87]. Using ah initio calculations, Chaput et al. [94] calculated the thermopower to be negative alongthe c axis and positive in the basal planes. The small value experimentally observed was thus ascribed to a compensation between the thermopowers of the two nonequivalent crystallographic axes. Yet, while certainly reasonable, this prediction awaits experimental verification on epitaxial thin films or large single crystals. 

Investigations of the CePtSn properties have shown that this compound is a Kondo system with antiferromagnetic ordering (Sakurai et al. 1990b, Nishigori et al. 1993). The measurements of resistivity and thermopower have been carried out on a single crystal by Bando et al. (1994) (fig. 35). Anisotropy of the properties in three directions is... 

Fig. 35. Temperature dependence of the resistivity and thermopower of single crystal CePtSn directed along the (a) X axis, (b) V axis and (c) Z axis. The arrows indicate the ordering temperatures Tfj and (Bando et al. 1994).

To cite a typical thermopower measurement [191], the CP sample is mounted across two single-crystal quartz blocks maintained at two different temperatures, usually a difference of 1°K. A thermocouple is also used to monitor the temperature difference. During the measurement, the temperature difference is achieved slowly (over 10 mins, e.g.). The voltages across the sample and the thermocouple are monitored with a nanovoltmeter. The slope of the thermovoltage of the sample vs. that of the thermocouple yields the sample thermopower, after correction for contact contributions. 

Yamashita K, Funato T, Suzuki Y, Teramachi S, Doi Y (2003) Characteristic interactions between poly(hydroxybutyrate) depolymerase and poly [(R)-3-hydroxybutyrate] film studied by a quartz crystal microbalance. Macromol Biosci 3 694—702 Yang L, Setyowati K, Li A, Gong S, Chen J (2008) Reversible infrared actuation of carbon nanotube-liquid crystalline elastomer nanocomposites. Adv Mater 20 2271-2275 Yu C, Shi L, Yao Z, Li D, Majumdar A (2005) Thermal conductance and thermopower of an individual single-wall carbon nanotube. Nano Lett 5 1842-1846 Yu H, Qin Z, Zhou Z (2011) Cellulose nanocrystals as green fillers to improve crystallization and hydrophilic property of poly(3-hydroxybut3uate-co-3-hydroxyvalerate). Prog Nat Sci Mater Int 21 478 84... 

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