Search results for "Ternary compound"

Nb 4 Te 17 I 4 , a New Pseudo One‐Dimensional Solid‐State Polytelluride

1994

The new ternary compound Nb4Te17I4 has been prepared and structurally characterized. It crystallizes in the monoclinic system, space group C2/c with unit-cell parameters a = 16.199(4), b = 8.128(2), c = 27.355(6) A, β = 110.84(2)°, Z = 4. The structure consists of infinite one-dimensional niobium/tellurium chains running parallel to the crystallographic c direction. The chains are separated by iodine atoms. Short and long metal–metal distances alternate in the sequence of three consecutive short bonds ([d ≈ 3.1 – 3.2 A) and one long (d = 4.268 A) metal–metal separation. Each Nb atom is eight-coordinate. The composition of the chain is ∞11[(Nb5+)2(Nb4+)2(Te22−)4(Te32−)3(I−)4].

Energy leaks through the optical barrier created by H+ implantation in BaTiO3 and LiNbO3 planar waveguides

1998

Abstract The energy leaks through the index barrier created by the proton implantation process are put in evidence in planar optical waveguides made in BaTiO 3 and LiNbO 3 substrates. The selective detection of the light emerging from the guiding region permits to measure the optical attenuation of the guided wave. The results obtained on mono or twice implanted LiNbO 3 and BaTiO 3 waveguides are presented and discussed. It is shown that the light confinement is better in BaTiO 3 than in LiNbO 3 .

Structural and optical properties of Fe and Zn substituted CuInS2 nanoparticles synthesized by a one-pot facile method

2015

We substitute indium present in the CuInS2 ternary compound by iron and zinc using a facile one-pot synthesis method. The quaternary compound of CuIn1−xMxS2 (M = Fe and Zn) was synthesized by dissolving CuCl, InCl3, FeCl3, Zn(ac)2 and SC(NH2)2 as precursors in 1-octadecene, oleylamine and oleic acid as non-coordinating, coordinating and capping agent solvents, respectively. Oleic acid, oleylamine and thiourea were used respectively as a hard Lewis base, borderline Lewis base (in comparison with oleic acid) and soft Lewis base to form appropriate complexes. The complex formation, structure, and optical properties of CuIn1−xMxS2 (M = Fe and Zn) nanoparticles were studied by Fourier transform …

Properties of the quaternary half-metal-type Heusler alloyCo2Mn1−xFexSi

2006

This paper reports on the bulk properties of the quaternary Heusler alloy Co2Mn1�xFexSi with the Fe concentration x =0,1/2,1. All samples, which were prepared by arc melting, exhibit L21 long-range order over the complete range of Fe concentration. The structural and magnetic properties of the Co2Mn1�xFexSi Heusler alloys were investigated by means of x-ray diffraction, high- and low-temperature magnetometry, Mossbauer spectroscopy, and differential scanning calorimetry. The electronic structure was explored by means of highenergy photoemission spectroscopy at about 8 keV photon energy. This ensures true bulk sensitivity of the measurements. The magnetization of the Fe-doped Heusler alloys …

Photoluminescence of chromium(III)-doped silicoaluminophosphate with AFI structure

1994

Enhanced photorefractive properties of Bi-doped Sn2P2S6

2008

International audience; Enhanced photorefractive properties of tin hypothiodiphosphate (Sn2P2S6) crystals as a result of Bi doping are presented. These new crystals were obtained by the vapor-transport technique using stoichiometric Sn2P2S6 composition with an additional amount of Bi up to 0.5 mol. % in the initial compound. The bandgap edges of the obtained crystals are located at ~750 nm and shift toward the red wavelengths with increasing Bi concentration. Sn2P2S6:Bi crystals are found to exhibit larger two-beam coupling gain coefficients (up to 17 cm−1 at a wavelength of 854 nm) as compared to (i) pure Sn2P2S6 (2.5 cm−1 at 854 nm), (ii) Sn2P2S6 crystals modified by the growth conditions…

Optical characterization of YCa4O(BO3)3 and Nd:YCa4O(BO3)3 crystals

2007

International audience; We report a complete optical characterization of YCa4O(BO3)3 and Nd:YCa4O(BO3)3 crystals. We studied the relative orientation between the dielectric and the crystallographic frames as a function of the wavelength and performed accurate phase-matching angles measurements for second harmonic generation, using a single crystal cut as a sphere. We also recorded polarized luminescence spectra of Nd:YCOB along the principal axes of the dielectric frame. For both crystals, we measured the gray-tracking and the thermo-optic properties as a function of temperature and wavelength using oriented slabs. Finally, we measured all their dielectric and electro-optic coefficients, as…

First-principles study of the amorphous In3SbTe2phase change compound

2013

Ab initio molecular dynamics simulations based on density functional theory were performed to generate amorphous models of the phase change compound In${}_{3}$SbTe${}_{2}$ by quenching from the melt. In-Sb and In-Te are the most abundant bonds with only a minor fraction of Sb-Te bonds. The bonding geometry in the amorphous phase is, however, strongly dependent on the density in the range 6.448--5.75 g/cm${}^{3}$ that we investigated. While at high density the bonding geometry of In atoms is mostly octahedral-like as in the cubic crystalline phase of the ternary compound In${}_{3}$SbTe${}_{2}$, at low density we observed a sizable fraction of tetrahedral-like geometries similar to those pres…

Preparation and characterisation of Na 2 S and ZnSO 4 nanoparticles in water/sodium bis(2-ethylhexyl)sulphosuccinate/ n -heptane microemulsions

2001

The preparation procedure for nanoparticles of the water-soluble salts Na2S and ZnSO4, two commonly used reagents to synthesise ZnS nanoparticles, by evaporation of volatile components of salt-containing water-in-oil microemulsions is described. In suitable conditions, the evaporation leads to the formation of dry salt–surfactant composites and to the formation of Na2S or ZnSO4 nanoparticles. It was found that the salt–surfactant composites can be totally redissolved in a dry apolar organic solvent allowing the formation of virtually water-free solutions containing a considerable amount of the water-soluble salts. The presence of nanoparticles in these solutions and in the composites has be…

Synthesis of high surface area perovskite catalysts by non-conventional routes

1997

Abstract The use of rare earth-containing perovskite oxides as total oxidation catalysts faces to the difficulty of obtaining high surface area materials and the need of calcination at high temperatures for its synthesis. In this work, perovskite NdCoO3 catalysts with relatively high surface areas were synthesized at soft calcination conditions by two non-conventional routes: heteronuclear organic complexes and amorphous precursors obtained by freeze-drying of nitrates solutions. Depending on the method used, different degrees of homogeneity in the bulk distribution of the component cations, oxygen non-stoichiometry as well as surface Co/Nd atomic ratios are obtained. In this way, the synth…