Low resistance Cu[3]Ge compounds formation by the lowtemperature treatment of Cu/Ge system in atomic hydrogen

The research deals with the regularities for Cu[3]Ge compound formation under the low temperature treatment of a double-layer Cu/Ge system deposited on i-GaAs substrate in atomic hydrogen flow. The treatment of a Cu/Ge/i-GaAs system with layer thicknesses, respectively, of 122 and 78 nm, in atomic hydrogen with a flow rate of 10{15} at.·сm{-2} s{-1} for a duration of 2.5{-10} min at room temperature, leads to an interdiffusion of Cu and Ge and formation of a polycrystalline film containing stoichiometric phase Cu[3]Ge. The film consists of vertically oriented grains of dimensions 100-150 nm and has a minimum specific resistance of 4.5 [mu omega] сm. Variation in the treatment duration of Cu/Ge/i-GaAs samples in atomic hydrogen affects Cu and Ge distribution profiles, the phase composition of films formed, and the specific resistance of the latter. As observed, Cu3Ge compound synthesis at room temperature demonstrates the stimulative effects characteristic of atomic hydrogen treatment for both Cu and Ge diffusion and for the chemical reaction of Cu[3]Ge compound generation. Activation of these processes can be conditioned by the energy released during recombination of hydrogen atoms adsorbed on the surface of a Cu/Ge/i-GaAs sample

Applications of π-photon-induced transparency in two-frequency pulse electron paramagnetic resonance experiments

Bichromatic pulses were demonstrated to substitute the second mw source both in stimulated soft electron spin echo envelope modulation (SS-ESEEM) and four-pulse double electron-electron resonance (DEER) experiments. As such, the results were compared to those obtained using traditional techniques. The behavior of bichromatic pulses which fulfill the transparency or near-transparency condition was investigated, and recommendations for obtaining optimum results were given

Crystal structures of binuclear Bi(III) chloride and bromide complexes with some cations — Alkylated pyridine derivatives

© 2017, Pleiades Publishing, Ltd. By a reaction of [BiX 6 ] 3– with salts of various N-alkylated pyridine derivatives in 2M HX (X = Cl, Br), (N-BzPy) 4 [Bi 2 X 10 ] complexes (X = Cl (1), Br (2), (4-MePyH) 4 [Bi 2 Cl 10 ] (3)) are obtained and structurally characterized

Polymeric hybrid iodoplumbates and iodobismuthates containing mono- and bisalkylated derivatives of 1,2-bis(4-pyridyl)ethylene: Structural and optical features

© 2017 Elsevier B.V.Reactions of PbI2 with N-alkylated derivatives of 1,2-bis(4-pyridyl)ethylene (bpen) MeBpenI and Me2BpenI2 result in 1D-polymeric complexes [{Pb(MeBpen)I3}] (1) and (Me2bpen)[{PbI3}]2 (2). For both compounds, band gap values were determinated experimentally; 1 demonstrates weak red luminescence. Binuclear hybrid iodobismuthate [Bi2(MeBpen)2I8] (3) was obtained by the similar scheme using BiI3 instead of PbI2

Heterogeneous bromination of alkenes using Bi(III) polybromide complexes as {Br<inf>2</inf>} source

© 2016 The Royal Society of Chemistry.A new polybromide Bi(iii) complex (PyH)3{[Bi2Br9](Br2)} was synthesized and characterized by XRD and other methods. This compound is able to act as a selective bromination agent towards various types of substituted alkenes

Use of the macrocyclic ligand cucurbit[6]uril for isolation of tetranuclear lanthanide aquahydroxo-carboxylate complexes from aqueous solutions

The tetranuclear lanthanide complexes {[Ln4(μ3-OH) 4(μ2-OH)2(C5NH 4COO)2 (H2O)4-(C36H 36N24O12)2][Ln(H2O) 8]1.5[Ln(H2O)6(NO3) 2]0.5} (NO3)9•nH2O (Ln = Ho, Gd, or Er) were prepared by heating (130 °C) aqueous solutions of lanthanide nitrates, cucurbit[6]uril (C36H36N 24O12), and 4-cyanopyridine. The tetradentate coordination of the macrocyclic cucurbit[6]uril ligands through the portals leads to the formation of sandwich compounds, in which the tetranuclear hydroxo complex is located between two macrocyclic molecules. The polynuclear complexes are additionally stabilized by the chelating effect of the isonicotinate ligands generated by hydrolysis of 4-cyanopyridine. In the complexes, the aromatic moiety of the isonicotinate ion is encapsulated into the hydrophobic inner cavity of cucurbit[6]uril. In the absence of cucurbit[6]uril, the reaction with 4-cyanopyridine produces only the polymeric complexes [Nd(C5NH 4COO)3(H2O)2] and [Ln(C 5NH4COO)2(H2O)4]NO 3 (Ln = Pr, Sm, or Gd), whose structures were established by X-ray diffraction. In water and aqueous solutions of nonionic and cationic surfactants, irreversible changes of the tetranuclear fragment of the complex (Ln = Gd) were observed after storage for two days, whereas the anionic surfactant stabilizes the complexes. © 2006 Springer Science+Business Media, Inc

Easy-plane to easy-axis anisotropy switching in a Co(ii) single-ion magnet triggered by the diamagnetic lattice

Single ion magnets SIMs with large magnetic anisotropy are promising candidates for realization of single molecule based magnetic memory and qubits. Creation of materials with magnetically uncoupled spatially separated SIMs requires dilution in a diamagnetic matrix. Herein, we report that progressive dilution of paramagnetic Co II by diamagnetic Zn II in the SIM [CoxZn 1 amp; 8722;x piv 2 2 NH2 Py 2], x 1 0 beyond a threshold of 50 reveals an abrupt structural change, where the distorted tetrahedral Zn coordination structure is superimposed on the remaining Co ions, which were initially in a distorted octahedral environment. Dilution induced structure modification switches the magnetic anisotropy from easy plane D 36.7 cm amp; 8722;1 to easy axis type D amp; 8722;23.9 cm amp; 8722;1 , accompanied by a fivefold increase of the magnetic relaxation time at 2 K. Changes of the static and dynamic magnetic properties are monitored by electron paramagnetic resonance spectroscopy and AC susceptibility measurements. Complementary quantum chemical ab initio calculations quantify the influence of structural changes on the electronic structure and the magnetic anisotropy. Thus, magnetic dilution hits two goals at once, the creation of isolated magnetic centres and an improvement of their SIM propertie

Effective Field and the Bloch-Siegert Shift at Bihromatic Excitation of Multiphoton EPR

The dynamics of multiphoton transitions in a two-level spin system excited by transverse microwave and longitudinal RF fields with the frequencies w_{mw} and w_{rf}, respectively, is analyzed. The effective time-independent Hamiltonian describing the "dressed" spin states of the "spin + bichromatic field" system is obtained by using the Krylov-Bogoliubov-Mitropolsky averaging method. The direct detection of the time behavior of the spin system by the method of nonstationary nutations makes it possible to identify the multiphoton transitions for resonances w_{0} = w_{mw} + rw_{rf} (w_{0} is the central frequency of the EPR line, r = 1, 2), to measure the amplitudes of the effective fields of these transitions, and to determine the features generated by the inhomogeneous broadening of the EPR line. It is shown that the Bloch-Siegert shifts for multiphoton resonances at the inhomogeneous broadening of spectral lines reduce only the nutation amplitude but do not change their frequencies.Comment: 6 pages, 5 figure