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TiNiSn-based half-Heusler alloys have been of significant interest for their potential as thermoelectric materials, which arises from their promising electronic transport properties. They exhibit high Seebeck coefficients and moderate electrical resistivity values but have comparatively high lattice thermal conductivities ([κ.sub.L]) that need to be reduced. A significant reduction in [κ.sub.L] with substitutions of large concentrations of Zr (y ≥ 25%) in [Ti.sub.1-y][Zr.sub.y]Ni[Sn.sub.0.95][Sb.sub.0.05] is observed and attributed to mass fluctuation scattering. In contrast, minute amounts of Sb-doping (x ≤ 5%) at the Sn-site in TiNi[Sn.sub.1-x][Sb.sub.x] gives rise to non- systematic increase in [κ.sub.L]. Extensive micro-structural analysis indicate a correlation between [κ.sub.L] and the average grain diameter of these materials. The two different phonon scattering mechanisms to reduce [κ.sub.L] are discussed in the Ti and Zr-based half-Heusler alloys., 1. Introduction Over the past few decades, there has been a revived interest in the field of thermoelectricity. New and advanced thermoelectric (TE) materials have been investigated as an alternate [...]

Ba(sub 8)Ga(sub 16)Si(sub x)Ge(30-x) were synthesized and their structural and electrical properties compared to those of similar type-I clathrates (Ba(sub 8)Ga(sub 16)Si(sub x)Ge(30-x)and Sr(sub 8)Ga(sub 16)Si(sub x)Ge(30-x)). The increasing Si content is accompanied by a slight increase in the absolute Seeback coefficient even as the carrier concentration increases and the resistivity decreases.

Research into the thermoelectric properties of semimetallic (Zr, Hf)CoSb half-Heusler phases is presented.

The transport characteristics of Ru0.5Pd0.5Sb3 from 300 down to 4 K were measured and contrasted with those of the binary-skutterudite antimonides. Specifically, the lattice thermal conductivity of this compound was substantially lower than that of CoSb3 and IrSb3. This was attributed to the mixed-valency of ruthenium in this compound. The ruthenium in this compound was observed to be in the Ru(super 4+)- and Ru(super 2+)-valence states in approximately equal proportions.

Various p-type samples of [Ni.sub.y][Mo.sub.3][Sb.sub.7-x][Te.sub.x] (y

The physical, compositional and selected optical properties of silica-clad erbium-doped yttrium aluminosilicate glass optical fibers derived from undoped [Er.sup.3+]-doped yttrium aluminum garnet (YAG) crystals are analyzed. The YAG-derived fibers are noncrystalline and the core/clad interface has shown that the diffusion has played a large role in this amorphization.

The synthesis, single-phase structure and good thermal stability of the indium and ytterbium double-filled skutterudites [In.sub.0.1][Yb.sub.y][Co.sub.4][Sb.sub.12] (y = 0.0-0.2) are described. A high figure of merit ZT displayed by the system in a fairly wide temperature regime has made it a promising candidate for power generation in the medium temperature regime.

A series of Yb-filled Ge-compensated skutterudites is synthesized, their thermoelectric properties are measured and the results are analyzed. Although substitutional doping allows increase Yb incorporation, there is a deterioration of the thermopower and resistivity at elevated temperatures.

Photoinduced phenomena are of general interest for new materials. Photoinduced polymerization and adsorption of oxygen are well known in fullerenes. However, there are no reports of similar photochemical behavior in [...]