Microstructural Instability and Its Effects on Thermoelectric Properties of SnSe and Na-Doped SnSe.

Effects of thermal cycling on the microstructure and thermoelectric properties are studied for the undoped and Na-doped SnSe samples using X-ray computed tomography and property measurements. It is observed that thermal cycling causes significant cracks to develop, which decrease both the electrical and lattice thermal conductivities but do not affect the thermopower. The values are drastically reduced after the repeated heat treatment.

NaSnSbGeO, an Air-Stable Solid-State Na-Ion Conductor.

The structure of a NaSnGeO phase was established via single-crystal X-ray diffraction. Unusually large displacement parameters of Na atoms suggested the possibility of Na ionic conductivity. To create Na deficiencies and thus increase the Na mobility in NaSnGeO, Sn cations were partially substituted with Sb.

Optimized electronic properties and nano-structural features for securing high thermoelectric performance in doped GeTe.

Recently, thermoelectric (TE) materials have been attracting great attention due to their improved capability to convert heat directly into electricity. PbTe-based TE materials are among the most competitive ones; however, lead toxicity limits their potential applications. Thus, the current focus in the field is on the discovery of lead-free analogues.

Enhancing the thermoelectric performance of SnGeTe via doping with Sb/Bi and alloying with CuTe: Optimization of transport properties and thermal conductivities.

The current work provides a comparative study of the thermoelectric properties of the SnGeTe phases doped with Sb and Bi and alloyed with CuTe. The SnGeTe composition was chosen based on the fact that it delivers the highest ZT value within the SnGeTe series (x≤ 0.5).

Highly dense SrSmDy□TiNbO/ZrO composite preparation directly through spark plasma sintering and its thermoelectric properties.

The SrSmDy□TiNbO/ZrO composite was directly prepared through spark plasma sintering. This approach limited the grain growth and facilitated the achievement of a narrow grain size distribution due to fast sintering and ZrO effects. Thermal conductivity declined to 1.

The updated Zn-Sb phase diagram. How to make pure ZnSb ("ZnSb").

The Zn-Sb system contains two well-known thermoelectric materials, Zn1-δSb and Zn13-δSb10 ("Zn4Sb3"), and two other phases, Zn9-δSb7 and Zn3-δSb2, stable only at high temperatures. The current work presents the updated phases diagram constructed using the high-temperature diffraction studies and elemental analysis. All phases are slightly Zn deficient with respect to their stoichiometric compositions, which is consistent with their p-type charge transport properties.

Synthetic Approach for (Mn,Fe)(Si,P) Magnetocaloric Materials: Purity, Structural, Magnetic, and Magnetocaloric Properties.

A conventional solid-state approach has been developed for the synthesis of phase-pure magnetocaloric MnFeSiP materials (x = 0.6, 0.7, 0.

AlFeCoB (x = 0-0.30): T Tuning through Co Substitution for a Promising Magnetocaloric Material Realized by Spark Plasma Sintering.

AlFeB and AlFeCoB (x = 0-0.30) were synthesized from the elements in three different ways. The samples were characterized by powder X-ray diffraction, Rietveld refinements, energy-dispersive X-ray spectroscopy, and magnetic measurements.

Identification, structural characterization and transformations of the high-temperature Zn9-δSb7 phase in the Zn-Sb system.

The Zn9-δSb7 phase has been identified via high-temperature powder diffraction studies. Zn9-δSb7 adopts two modifications: an α form stable between 514 °C and 539 °C and a Zn-poorer β form stable from 539 °C till its melting temperature of 581 °C. The Zn9-δSb7 structure was solved from the powder data using the simulated annealing approach.

Synthesis and evaluation of new salicylaldehyde-2-picolinylhydrazone Schiff base compounds of Ru(II), Rh(III) and Ir(III) as in vitro antitumor, antibacterial and fluorescence imaging agents.

Reaction of salicylaldehyde-2-picolinylhydrazone (HL) Schiff base ligand with precursor compounds [{(p-cymene)RuCl2}2] 1, [{(C6H6)RuCl2}2] 2, [{Cp*RhCl2}2] 3 and [{Cp*IrCl2}2] 4 yielded the corresponding neutral mononuclear compounds 5-8, respectively. The in vitro antitumor evaluation of the compounds 1-8 against Dalton's ascites lymphoma (DL) cells by fluorescence-based apoptosis study and by their half-maximal inhibitory concentration (IC50) values revealed the high antitumor activity of compounds 3, 4, 5 and 6. Compounds 1-8 render comparatively lower apoptotic effect than that of cisplatin on model non-tumor cells, i.

Crystal cluster growth and physical properties of the EuSbSe3 and EuBiSe3 phases.

Syntheses of europium metal, selenium powder, and the Sb(2)Se(3)/Bi(2)Se(3) binaries were observed to produce crystal clusters of the EuSbSe(3) and EuBiSe(3) phases. These phases crystallize with the P2(1)2(1)2(1) space group and can be easily identified based on their growth habits, forming large clusters of needles. Previous literature suggested that their structure is charge-balanced with all europium atoms in the divalent state and one-quarter of the selenium atoms forming trimers.

The low-symmetry lanthanum(III) oxotellurate(IV), La10Te12O39.

Single crystals of deca-lanthanum(III) dodeca-oxotellurate(IV), La10Te12O39, were obtained by reacting La2O3 and TeO2 in a CsCl flux. Its crystal structure can be viewed as a three-dimensional network of corner- and edge-sharing LaO8 polyhedra with Te(IV) atoms filling the inter-stitial sites. The Te(IV) atoms with their 5s (2) electron lone pairs distort the LaO8 polyhedra through variable Te-O bonds.

Electronically induced ferromagnetic transitions in Sm5Ge4-type magnetoresponsive phases.

The correlation between magnetic and structural transitions in Gd(5)Si(x)Ge(4-x) hampers the studies of valence electron concentration (VEC) effects on magnetism. Such studies require decoupling of the VEC-driven changes in the magnetic behavior and crystal structure. The designed compounds, Gd(5)GaSb(3) and Gd(5)GaBi(3), adopt the same Sm(5)Ge(4)-type structure as Gd(5)Ge(4) while the VEC increases from 31  e(-)/formula in Gd(5)Ge(4) to 33  e(-)/formula in Gd(5)GaPn(3) (Pn: pnictide atoms).

Synthesis, crystal structure, and electronic properties of the tetragonal (RE(I)RE(II))3SbO3 phases (RE(I) = La, Ce; RE(II) = Dy, Ho).

In our efforts to tune the charge transport properties of the recently discovered RE(3)SbO(3) phases (RE is a rare earth), we have prepared mixed (RE(I)RE(II))(3)SbO(3) phases (RE(I) = La, Ce; RE(II) = Dy, Ho) via high-temperature reactions at 1550 °C or greater. In contrast to monoclinic RE(3)SbO(3), the new phases adopt the P4(2)/mnm symmetry but have a structural framework similar to that of RE(3)SbO(3). The formation of the tetragonal (RE(I)RE(II))(3)SbO(3) phases is driven by the ordering of the large and small RE atoms on different atomic sites.

Gd4Ge(3-x)Pn(x) (Pn = P, Sb, Bi, x = 0.5-3): stabilizing the nonexisting Gd4Ge3 binary through valence electron concentration. Electronic and magnetic properties of Gd4Ge(3-x)Pn(x).

Gd(4)Ge(3-x)Pn(x) (Pn = P, Sb, Bi; x = 0.5-3) phases have been prepared and characterized using X-ray diffraction, wavelength-dispersive spectroscopy, and magnetization measurements. All Gd(4)Ge(3-x)Pn(x) phases adopt a cubic anti-Th(3)P(4) structure, and no deficiency on the Gd or p-element site could be detected.

Electron-deficient Eu(6.5)Gd(0.5)Ge6 intermetallic: a layered intergrowth phase of the Gd5Si4- and FeB-type structures.

A novel electron-poor Eu(6.5)Gd(0.5)Ge₆ compound adopts the Ca₇Sn₆-type structure (space group Pnma, Z = 4, a = 7.

Decoupling the electrical conductivity and Seebeck coefficient in the RE2SbO2 compounds through local structural perturbations.

Compromise between the electrical conductivity and Seebeck coefficient limits the efficiency of chemical doping in the thermoelectric research. An alternative strategy, involving the control of a local crystal structure, is demonstrated to improve the thermoelectric performance in the RE(2)SbO(2) system. The RE(2)SbO(2) phases, adopting a disordered anti-ThCr(2)Si(2)-type structure (I4/mmm), were prepared for RE = La, Nd, Sm, Gd, Ho, and Er.

Crystal structure, coloring problem and magnetism of Gd(5-x)Zr(x)Si4.

Ternary Gd(5-x)Zr(x)Si(4) silicides were synthesized by arc melting of the constituent elements and subsequent heat treatments. The Gd(5-x)Zr(x)Si(4) phases adopt the orthorhombic Gd(5)Si(4)-type (space group Pnma) structure for x≤ 0.25 and the tetragonal Zr(5)Si(4)-type (space group P4(1)2(1)2) structure for x≥ 1.

Mono and dinuclear arene ruthenium(II) triazoles by 1,3-dipolar cycloadditions to a coordinated azide in ruthenium(II) compounds.

The dimeric η(6)-hexamethylbenzene ruthenium(II) triazole compounds of formulation [{(η(6)-C(6)Me(6))Ru(N(3)C(2)(CO(2)R)(2))}(2)(μC(2)O(4))] have been synthesized by 1,3-diploar cycloadditions of coordinated azido compound [{(η(6)-C(6)Me(6))Ru(L(1))N(3)}] (1) with substituted acetylene, RO(2)CC(2)CO(2)R via unexpected oxidation of the coordinated ligand to oxalate (where; L(1) = 5-hydroxy-2-(hydroxymethyl)-4-pyrone; R = Me, 3 or Et, 4). In contrast, a similar 1,3-dipolar cycloaddition reaction of [{(η(6)-C(6)Me(6))Ru(L(2))N(3)}] (2) (where; L(2) = tropolone) with acetylene yielded the monomeric triazole compound [(η(6)-C(6)Me(6))Ru(L(2)){N(3)C(2)(CO(2)R)(2)}] (where; R = Me, 5; Et, 6). The compounds were characterized by spectroscopy and the structures of representative compounds 4 and 6 have been determined by single crystal X-ray diffraction.

Synthesis, crystal and electronic structures of new narrow-band-gap semiconducting antimonide oxides RE(3)SbO(3) and RE(8)Sb(3-delta)O(8), with RE = La, Sm, Gd, and Ho.

In the search for high-temperature thermoelectric materials, two families of novel, narrow-band-gap semiconducting antimonide oxides with the compositions RE(3)SbO(3) and RE(8)Sb(3-delta)O(8) (RE = La, Sm, Gd, Ho) have been discovered. Their synthesis was motivated by attempts to open a band gap in the semimetallic RESb binaries through a chemical fusion of RESb and corresponding insulating RE(2)O(3). Temperatures of 1350 degrees C or higher are required to obtain these phases.

Composition, structure, bonding and thermoelectric properties of "CuT2P3" and "CuT4P3", members of the T(1-x)(CuP3)x series with T being Si and Ge.

Through electron microprobe analysis, X-ray and neutron diffraction, it has been established that "CuT(2)P(3)" and "CuT(4)P(3)" (T = Si, Ge) adopt the cubic or tetragonally distorted zinc blende structures in which two element mixtures are present on both atomic sites. One site contains the Cu/T mixture while the other site is occupied by T and P. The structure of "CuT(2)P(3)" and "CuT(4)P(3)" can be derived from that of silicon or germanium, in which the single Si or Ge site is broken into two independent sites by the preferential Cu and P substitution.

Gd(5)Si(4-x)Bi(x) structures: novel slab sequences achieved by turning off the directionality of nearest-slab interactions.

Substitution of Bi for Si leads to the complete cleavage of the interslab dimers T-T in the Gd(5)Si(4-x)Bi(x) system with x = 1.58 - 2.42 (T is a mixture of Si and Bi).

High-temperature order-disorder transition in CoCr2Se4 and trapping co disorder in monoclinic CoCr2Se4: structural features of Cu(1-x)Co(x)Cr2Se4 phases.

X-ray diffraction studies on the Cu(1-x)Co(x)Cr(2)Se(4) system (x = 0, 0.2, 0.4, 0.

Gd(5)Si(4-x)P(x): targeted structural changes through increase in valence electron count.

Phase transformations in the Gd(5)Si(4-x)P(x) system (0 View Article and Find Full Text PDF