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Tuning of the magnetic properties of intermetallic materials is increasingly gaining interest in the chemistry community. We report on the successful synthesis and magnetic characterizations of the two new quaternary boride series MRh6- nRu nB3 (M = Co, Ni; 1 ≤ n ≤ 5). Powder samples have been synthesized by arc-melting the elements under purified argon in a water-cooled copper crucible. The products were characterized by powder X-ray diffraction through Rietveld refinements as well as EDX measurements. All phases crystallize in the hexagonal Th7Fe3 structure type (space group P63 mc, no. 186, Z = 2). In the Co-based series, the lattice parameters decrease linearly with increasing ruthenium content, whereas in the Ni-based series they remain nearly constant for the Rh-rich side then decrease with increasing Ru content. Significant ferromagnetic interactions are observed for the Co-based series, and they decrease linearly with increasing Ru content with magnetic moments decreasing from 0.74 µB (CoRh5RuB3) to 0.13 µB (CoRhRu5B3) at 5 K and 5 T. Pauli paramagnetism dominates the Ni-based series. [ABSTRACT FROM AUTHOR]

A solid solution of Ti1-xNbxS3 composition (x = 0, 0.05, 0.07, 0.10) was synthesized by solid-liquid-vapor reaction followed by spark plasma sintering. The obtained compounds crystallize in the monoclinic ZrSe3 structure type. For the x = 0.07 sample, a mixture of both A and B variants of the MX3 structure is evidenced by transmission electron microscopy. This result contrasts with those of pristine TiS3, prepared within the same conditions, which crystallizes as a large majority of A variant. Thermoelectric properties were investigated in the temperature range 323 to 523 K. A decrease in the electrical resistivity and absolute value of the Seebeck coefficient is observed when increasing x due to electron doping. The lattice component of the thermal conductivity is effectively reduced by the Nb for Ti substitution through a mass fluctuation effect and/or a disorder effect created by the mixture of both A and B variants. Due to the low carrier concentration and the semiconductor character of the doped compounds, the too low power factor values leads to ZT values that remain smaller by a factor of 50 than those of the TiS2 layered compound. [ABSTRACT FROM AUTHOR]

Single-phase polycrystalline samples of the compounds MRh6B3 (M = Fe, Co) as well as single crystals of CoRh6B3 have been synthesized by arc-melting the elements under a purified argon atmosphere in a water-cooled copper crucible. The characterization of the new phases was achieved by using single-crystal and powder X-ray diffraction as well as EDX measurements. The two phases are isotypic and crystallize in the hexagonal Th7Fe3 structure type (space group P63mc, no. 186, Z = 2). In this structure, the magnetically active atoms (Fe, Co) are preferentially found on only one of the three available rhodium sites, and together with rhodium they build a three-dimensional network of interconnected (Rh/M)3 triangles. Magnetic properties investigations show that both phases order ferromagnetically below Curie temperatures of 240 K (for FeRh6B3) and 150 K (for CoRh6B3). First-principles DFT calculations correctly reproduce not only the lattice parameters but also the ground state magnetic ordering in the two phases. These calculations also show that the long-range magnetic ordering in both phases occurs via indirect ferromagnetic coupling between the iron atoms mediated by rhodium. This magnetic structural model also predicts the saturation magnetizations to be 4.02 μB for FeRh6B3 (3.60 μB found experimentally) and 2.75 μB for CoRh6B3. Furthermore, both phases are predicted to be metallic conductors as expected for these intermetallic borides. [ABSTRACT FROM AUTHOR]

A denseTiS3sample has been processed by Spark PlasmaSintering. The structural analysis, obtained by coupling powder X-raydiffraction and transmission electron microscopy (TEM), shows thatthe A-variant of the ZrSe3-type structure is stabilizedfor the first time. Defects along the main atomic layer stacking directionsare evidenced by high-resolution TEM, which explain the peculiar X-raypowder diffraction patterns, with strongly anisotropic microstrains.The presence of these structural defects might explain the existenceof a metal-to-insulator transition with a charge localization below TMI≈ 325 K. Large absolute values ofthe Seebeck coefficient, in the range −700 ≤ S≤ −600 μV·K–1, are observed for 100 ≤ T≤ 600 K,together with a low thermal conductivity, κ = 2 W·K–1·m–1at 600 K. The T–1dependence of the lattice part ofκ indicates its phononic character. As the charge carrier concentrationmeasured by Hall effect is too low, n= 1.24 ×1018cm–3, extra doping would be necessaryto decrease its too high electrical resistivity (ρ300K∼ 1.4 Ω·cm) for thermoelectric applications. [ABSTRACT FROM AUTHOR]

A dense TiS3 sample is prepared by solid state reaction of a 1:4 mixture of Ti and S (evacuated quartz ampoule, 600 °C) followed by spark plasma sintering in vacuum and subsequent hot press molding (600 °C, 50 MPa, 10 min). [ABSTRACT FROM AUTHOR]