Search results for "Resistivity"
showing 10 items of 385 documents
Investigation of the Thermoelectric Properties of the Series TiCo1-xNixSnxSb1-x
2010
The effect of the simultaneous substitution of cobalt by nickel and antimony by tin in the solid solution TiCo1–xNixSnxSb1–x was systematically investigated. The number of valence electrons does not change by this substitution and therefore the resistivity stays semimetallic or semiconducting. The series were synthesized by arcmelting and the thermoelectric properties were determined. It was found out that the substitution of cobalt and antimony by nickel and tin reduces the thermal conductivity to 2 W·m–1·K–1 at 400 K. The reduction is caused by titanium rich prolate micro structures that were found by energy dispersive X-ray spectroscopy investigations. The Seebeck coefficient and the res…
Structure and Properties of One-Dimensional Heterobimetallic Polymers Containing Dicyanoaurate and Dirhodium(II) Fragments
2012
The synthesis and characterization of compound [Rh(2)(O(2)CEt)(4)(H(2)O)(2)] (1) and one-dimensional heterobimetallic polymers K(n){Rh(2)(O(2)CEt)(4)[Au(CN)(2)]}(n) (2) and K(n){Rh(2)(O(2)CMe)(4)[Au(CN)(2)]}(n)·4nH(2)O (3), constructed from dirhodiumtetracarboxylato units, [Rh(2)(O(2)CR)(4)](+), and dicyanoaurate, [Au(CN)(2)](-), fragments are described. In both compounds 2 and 3 the resulting polymeric chains are nonlinear and have in common similar structural parameters, although the solid state supramolecular arrangement is very different. These structural differences explain the fact that complex 2 displays aurophilic interactions while this type of interactions are absent in complex 3.…
Pressure-dependent modifications in the optical and electronic properties of Fe(IO3)3: the role of Fe 3d and I 5p lone–pair electrons
2021
We have determined by means of optical-absorption experiments that Fe(IO3)3 is an indirect band-gap material with a band-gap energy of 2.1 eV. This makes this compound the iodate with the smallest band gap. We also found that under compression the band-gap energy has an unusual non-linear pressure dependence, which is followed by an abrupt and discontinuous decrease of the band gap at 24 GPa. The observed behavior is explained by means of density-functional calculations, which show that the behavior of the band gap is governed by the combined influence of Fe 4d and I 5p lone pair electrons. In addition, the abrupt decrease of the band-gap energy at 24 GPa is a consequence of a first-order s…
Strain induced renormalization of transport properties in UPt3 thin films
1996
The growth of sputter deposited UPt3 thin films on Al2O3 (1012), LaAlO3 (111) and SrTiO3 (111) was investigated. We found strongly 0001-textured growth of UPt3 in a small compositional range of 23–25% uranium content. For Al2O3-and LaAlO3-substrates no in-plane order could be observed whereas epitaxial growth was initiated on SrTiO3 (111): The growth can be identified as Vollmer-Weber like resulting in the formation of large lateral strain as a consequence of the growth mode and a lattice misfit of −4.3% between UPt3 (0001) and SrTiO3 (111). Strong deviations from the typical heavy-fermion characteristics in electronic transport properties like resistivity, magnetoresitivity and Hall-effect…
Simulation of Fundamental Properties of CNT- and GNR-Metal Interconnects for Development of New Nanosensor Systems
2012
Cluster approach based on the multiple scattering theory formalism, realistic analytical and coherent potentials, as well as effective medium approximation (EMA-CPA), can be effectively used for nano-sized systems modeling. Major attention is paid now to applications of carbon nanotubes (CNTs) and graphene nanoribbons (GNRs) with various morphology which possess unique physical properties in nanoelectronics, e.g., contacts of CNTs or (GNRs) with other conducting elements of a nanocircuit, which can be promising candidates for interconnects in high-speed electronics. The main problems solving for resistance C-Me junctions with metal particles appear due to the influence of chirality effects …
Scattering Processes in Nanocarbon-Based Nanointerconnects
2017
Cluster approach based on the multiple scattering theory (MST) formalism, realistic analytical and coherent potentials as well as effective medium approximation (EMA–CPA) can be effectively used for nanosized systems modelling. Major attention is paid now to applications of carbon nanotubes (CNTs) and graphene nanoribbons (GNRs) with various morphology which possess unique physical properties in nanoelectronics, e.g. contacts of CNTs or GNRs with other conducting elements of a nanocircuit, which can be promising candidates for interconnects in high-speed electronics. The main problems connected with the resistance of C–Me junctions with metal particles appear due to the influence of chirali…
Conductive nanostructures of MMX chains
2010
Crystals of [Pt-2(n-pentylCS(2))(4)I] show a transition from semiconductor to metallic with the increase of the temperature (conductivity is 0.3-1.4 S.cm(-1) at room temperature) and a second metallic metallic transition at 330 K, inferred by electrical conductivity measurements. X-ray diffraction studies carried out at different temperatures (100, 298, and 350 K) confirm the presence of three different phases. The valence-ordering of these phases is analyzed using structural, magnetic, and electrical data. Density functional theory calculations allow a further analysis of the band structure derived for each phase. Nanostructures adsorbed on an insulating surface show electrical conductivit…
Electropolymerization of non-substituted Mg(II) porphine: Effects of proton acceptor addition
2015
Abstract Electropolymerization of unsubstituted magnesium porphine in acetonitrile solutions possessing various proton-accepting properties has been studied. The overall rate of the polymer-product accumulation on the electrode surface has been established to be limited by the deprotonation step of intermediate species. This conclusion is based on the observed influence of proton-accepting additives, water or 2,6-dimethylpyridine (lutidine), on the Mg-porphine electrooxidation process. Lutidine addition into the polymerization bath enables one to enhance strongly the rate of the film growth and the efficiency of this process increases more than by a factor of two, redox, electric conductivi…
Short range charge/orbital ordering in La1−xSrxMn1−zBzO3 (B = Cu,Zn) manganites
2005
We have measured the reflectivity spectra of La1−x SrxMn1−zBzO3 (B = Cu, Zn; 0.17 x 0.30; 0 z 0.10) manganites over wide frequency (100–4000 cm −1 )a nd temperature (80–300 K) ranges. Besides the previously observed infrared active modes or mode pairs at about 160 cm −1 (external mode), 350 cm −1 (bond bending mode) and 590 cm −1 (bond stretching mode), we have clearly observed two additional phonon modes at about 645 and 720 cm −1 below the temperature T1 (T1 < TC), which coincides with the phase transition temperature when the system transforms from ferromagnetic metallic into a ferromagnetic insulator state. This transition is related to the formation of short range charge/orbitally orde…
LOCAL-MOMENT AND ITINERANT ANTIFERROMAGNETISM IN THE HEAVY-FERMION SYSTEM CE(CU1-XNIX)2GE2
1992
Elastic and inelastic neutron-scattering studies on the system Ce(Cu1−xNix)2Ge2 are reported. These measurements are complemented by measurements of the magnetic susceptibility, high-field magnetization, heat capacity, thermal expansion, electrical resistivity and thermopower. The results reveal an interesting T-x phase diagram consisting of two different antiferromagnetic phases for x 0.5. Further experimental evidence for different types of antiferromagnetic ordering derives from a line-shape analysis of the quasielastic neutron-scattering intensity, from magnetization and thermopower experiments.