Materials Literature
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Molecular metals normally require charge transfer between two different chemical species. We prepared crystals of [Ni(tmdt)2] (tmdt, trimethylenetetrathiafulvalenedithiolate) and carried out crystal structure analyses and resistivity measurements. The analyses and measurements revealed that these single-component mole…
Mg(OH) 2 nanocrystallines with rod-, tube-, needle-, or lamella-like morphologies have been synthesized by a hydrothermal reaction using different magnesium precursors and solvents as the reactants. The products appeared to have narrow size distributions with a monodisperse nature. Subsequent thermal decomposition at…
A purification method has been developed that provides for the removal of metal catalysts and impurity carbon from laser-oven-grown single-wall carbon nanotube (SWNT) material. The oxidation rate of SWNTs in air at elevated temperatures is correlated to the metal content of the sample. Sample purity is documented with…
Inelastic neutron-scattering study of a deuterated crystal of Rochelle salt confirms the existence of a resonant mode near 25 ${\mathrm{cm}}^{\ensuremath{-}1}$ at 50 K which softens with increasing temperature and becomes overdamped on approaching the phase transition to the ferroelectric phase. We argue that this mod…
We present the first muon spin rotation/relaxation study of a nematic liquid crystal (5CB). We identify four different positions for muonium addition to this compound by correlating the dominant peaks in the Fourier transform of the muon precession signal obtained in an applied transverse magnetic field. Experiments p…
A study has been made of the magnetic and transport properties of ${\mathrm{CuCr}}_{2}{\mathrm{S}}_{4}$ powder compacts consisting of nanosized crystallites synthesized by mechanical alloying of the constituent elements at ambient temperature. It is found that the material is a typical spin glass with a spin freezing…
A model of nonradiative transitions in spin-crossover molecules is developed. The model takes into account linear and quadratic terms of electron-vibrational interaction. The frequency effect is shown to arise from the quadratic term of this interaction. With account of the frequency effect analytical expressions are…
The low temperature (6 K) EPR spectrum of Cu 2+ in K 2 Zn(SO 4 ) 2 ·6H 2 O is characteristic for the ground state a | x 2 - y 2 ⟩- b | z 2 ⟩ with essentially the | x 2 - y 2 ⟩ state and 4.5% admixture of the | z 2 ⟩ state due to the zero-point motions. Temperature variations of the g and A parameters are characteristi…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTChemical Shielding Tensors for a Silicon−Carbon Double BondJarrod J. Buffy, Robert West, Michael Bendikov, and Yitzhak ApeloigView Author Information Department of Chemistry, University of Wisconsin-Madison Madison, Wisconsin 53706 Department of Chemistry and the Lise…
We report dc and ac magnetization of the newly discovered Cd-Mg-RE quasicrystals (RE = Gd, Tb, Dy, Ho, Er, Tm and Yb). For all the RE atoms except Yb, the temperature dependence of the dc magnetization obeys the Curie-Weiss law at higher temperatures, T >50 K. Estimated effective moments indicate that these atoms are…
The preparation and crystal structures of two oxalato-bridged FeII-FeIII mixed-valence compounds, [FeII(bpm)3]2[FeIII2(ox)5].8H2O (1) and FeII(bpm)3Na(H2O)2FeIII(ox)(3).4H2O (2) (bpm = 2,2'-bipyrimidine; ox = oxalate dianion) are reported here. Complex 1 crystallizes in the triclinic system, space group P1, with a = 1…
The nature of the attractive electron-electron interaction, leading to the formation of Cooper pairs in unconventional superconductors, has still to be fully understood and is subject to intensive research. Here we show that the sequence spin-Peierls, antiferromagnetism, superconductivity observed in (TMTTF) 2 PF 6 un…
Core-level Mn and Co 2p x-ray photoelectron spectroscopic studies give evidence for different spin states of Mn and Co in the two different phases of the ferromagnetic compound LaMn 0.5 Co 0.5 O 3 . Ferromagnetism in the high- T c ( T c ≈230 K) phase of the compound arises from Mn 3+ -O-Mn 3+ superexchange interaction…
Excited state absorption spectra from the 4f 2 levels of Pr 3+ in YPO 4 to 4f5d were measured at 293 and 77 K using a pulsed pump-probe technique. The spectra from the 1 D 2 manifold were recorded by employing a continuous wave probe, whilst those from the 3 P J - 1 I 6 states were recorded by using for the first time…
We have investigated transport and magnetic properties of a series of double-perovskite alloys in the system Sr 2 FeMo x W 1- x O 6 . These compounds exhibit a metal-insulator transition as a function of doping, x . The compounds with x in the range 1.0⩾ x ⩾0.3 show metallic behaviour in the resistivity while compound…
The construction of two-dimensional (2D) copper halide networks within a variety of perovskite hosts by a low-temperature topochemical method is demonstrated. Ion exchange between some layered perovskite oxides of the type A'[An - 1(M,M')nO3n + 1] (A' = alkali metal, H, NH4; A = alkaline earth, rare earth, or Bi; M,M'…
The synthesis and characterization of (Bu4N)4[S2W18O62].1.23MeCN.0.27H2O are reported. It crystallizes in the monoclinic space group C2/c with a = 22.389(6) A, b = 22.104(3) A, c = 25.505(5) A, beta = 95.690(15) degrees, V = 12560(5) A3, and Z = 4. The anion exists as the gamma* isomer, the second example of this isom…
A process for the large-scale production of 4-hydroxyvalerate (4HV)-containing biopolyesters with a new monomer composition was developed by means of high-cell-density cultivation applying recombinant strains of Pseudomonas putida and Ralstonia eutropha, harboring the PHA-biosynthesis genes phaC and phaE of Thiocapsa…
An unusual field-dependent slow magnetic relaxation and two distinct transitions were observed in a family of rare-earth--transition-metal complexes [Ln (bipy) $({\mathrm{H}}_{2}\mathrm{O}{)}_{4} M(\mathrm{CN}{)}_{6}] \ensuremath{\cdot}1.5$ (bipy) $\ensuremath{\cdot}4{\mathrm{H}}_{2}\mathrm{O}$ $(\mathrm{b}\mathrm{i}\…
We compare the results of measurements of the magnetic susceptibility Chi(T), the linear coefficient of specific heat Gamma(T)=C(T)/T and 4f occupation number nf(T) for the intermediate valence compounds YbXCu4 (X = Ag, Cd, In, Mg, Tl, Zn) to the predictions of the Anderson impurity model, calculated in the non-crossi…