Temperature dependence of the resistivity of Hg3–δAsF6

1982 ◽  
Vol 60 (9) ◽  
pp. 1348-1357 ◽  
Author(s):  
E. Batalla ◽  
W. R. Datars
Keyword(s):  
Fermi Surface ◽  
Temperature Dependence ◽  
Electron Scattering ◽  
Short Range ◽  
Linear Chain ◽  
Three Dimensional ◽  
One Dimensional ◽  
Anisotropic Superconductor ◽  
Short Range Ordering ◽  
Long Range Ordering

The resistivity of the linear-chain mercury compound Hg3–δAsF6 is reported in the temperature range 1.4–300 K. Electron scattering by one-dimensional and three-dimensional phonons on a cylindrical Fermi surface is used to calculate the temperature dependence of the resistivity which agrees with measurements of the resistivity between 4.2 and 90 K. The resistivity is determined by the Montgomery method which is extended to the case when electrical probes are not at the corners of a sample. The anisotropy ρc/ρa of the resistivity is in the range 95 ± 10 between 40 and 180 K. It is explained by a 1.4% undulation along the Fermi surface cylinders. Changes in the anisotropy give evidence of three-dimensional, long-range ordering at 120 K and short-range ordering of the mercury chains between 180 and 200 K reported previously. Hysteresis in the resistivity shows an unusual transition at 217 ± 3 K which is evident only upon cooling samples. There is no evidence of zero, c-axis resistivity below 4.1 K to support the suggestion that Hg3–δAsF6 is an anisotropic superconductor.

A 16-connected three-dimensional hydrogen-bonding network in tetrakis(4-aminopyridinium) perylene-3,4,9,10-tetracarboxylate octahydrate

2014 ◽  
Vol 70 (7) ◽  
pp. 668-671 ◽  
Author(s):  
Zhi-Hui Zhang ◽  
Jin-Long Wang ◽  
Ning Gao ◽  
Ming-Yang He
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Linear Chain ◽  
Three Dimensional ◽  
Organic Salt ◽  
Water Molecules ◽  
The Novel ◽  
One Dimensional ◽  
Connected Node ◽  
Hydrogen Bonding Network

The novel title organic salt, 4C5H7N2+·C24H8O84−·8H2O, was obtained from the reaction of perylene-3,4,9,10-tetracarboxylic acid (H4ptca) with 4-aminopyridine (4-ap). The asymmetric unit contains half a perylene-3,4,9,10-tetracarboxylate (ptca4−) anion with twofold symmetry, two 4-aminopyridinium (4-Hap+) cations and four water molecules. Strong N—H...O hydrogen bonds connect each ptca4−anion with four 4-Hap+cations to form a one-dimensional linear chain along the [010] direction, decorated by additional 4-Hap+cations attached by weak N—H...O hydrogen bonds to the ptca4−anions. Intermolecular O—H...O interactions of water molecules with ptca4−and 4-Hap+ions complete the three-dimensional hydrogen-bonding network. From the viewpoint of topology, each ptca4−anion acts as a 16-connected node by hydrogen bonding to six 4-Hap+cations and ten water molecules to yield a highly connected hydrogen-bonding framework. π–π interactions between 4-Hap+cations, and between 4-Hap+cations and ptca4−anions, further stabilize the three-dimensional hydrogen-bonding network.

scholarly journals Magnetic and Electronic Properties of π-d Interacting Molecular Magnetic Superconductor κ-(BETS)2FeX4 (X = Cl, Br) Studied by Angle-Resolved Heat Capacity Measurements

Crystals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 66 ◽  
Author(s):  
Shuhei Fukuoka ◽  
Sotarou Fukuchi ◽  
Hiroki Akutsu ◽  
Atsushi Kawamoto ◽  
Yasuhiro Nakazawa
Keyword(s):  
Magnetic Field ◽  
Heat Capacity ◽  
Magnetic Fields ◽  
Temperature Dependence ◽  
Three Dimensional ◽  
Magnetic Interaction ◽  
Spin Configuration ◽  
Magnetic Superconductor ◽  
Heat Capacity Measurements ◽  
Long Range Ordering

Thermodynamic picture induced by π-d interaction in a molecular magnetic superconductor κ-(BETS)2FeX4 (X = Cl, Br), where BETS is bis(ethylenedithio)tetraselenafulvalene, studied by single crystal calorimetry is reviewed. Although the S = 5/2 spins of Fe3+ in the anion layers form a three-dimensional long-range ordering with nearly full entropy of Rln6, a broad hump structure appears in the temperature dependence of the magnetic heat capacity only when the magnetic field is applied parallel to the a axis, which is considered as the magnetic easy axis. The scaling of the temperature dependence of the magnetic heat capacity of the two salts is possible using the parameter of |Jdd|/kB and therefore the origin of the hump structure is related to the direct magnetic interaction, Jdd, that is dominant in the system. Quite unusual crossover from a three-dimensional ordering to a one-dimensional magnet occurs when magnetic fields are applied parallel to the a axis. A notable anisotropic field-direction dependence against the in-plane magnetic field was also observed in the transition temperature of the bulk superconductivity by the angle-resolved heat capacity measurements. We discuss the origin of this in-plane anisotropy in terms of the 3d electron spin configuration change induced by magnetic fields.

Two cadmium(II) fluorous coordination compounds tuned by different bipyridines

2017 ◽  
Vol 73 (5) ◽  
pp. 424-429 ◽  
Author(s):  
Ya-Jie Kong ◽  
Peng Li ◽  
Li-Juan Han ◽  
Lu-Tong Fan ◽  
Peng-Peng Li ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Coordination Compounds ◽  
Linear Chain ◽  
Three Dimensional ◽  
Chain Structure ◽  
Water Molecules ◽  
Hydrogen Bond Acceptor ◽  
Small Surface ◽  
One Dimensional ◽  
Coordinated Water

Fluorine is the most electronegative element and can be used as an excellent hydrogen-bond acceptor. Fluorous coordination compounds exhibit several advantageous properties, such as enhanced high thermal and oxidative stability, low polarity, weak intermolecular interactions and a small surface tension compared to hydrocarbons. C—H...F—C interactions, although weak, play a significant role in regulating the arrangement of the organic molecules in the crystalline state and stabilizing the secondary structure. Two cadmium(II) fluorous coordination compounds formed from 2,2′-bipyridine, 4,4′-bipyridine and pentafluorobenzoate ligands, namely catena-poly[[aqua(2,2′-bipyridine-κ2 N,N′)(2,3,4,5,6-pentafluorobenzoato-κO)cadmium(II)]-μ-2,3,4,5,6-pentafluorobenzoato-κ2 O:O′], [Cd(C7F5O2)2(C10H8N2)(H2O)] n , (1), and catena-poly[[diaquabis(2,3,4,5,6-pentafluorobenzoato-κO)cadmium(II)]-μ-4,4′-bipyridine-κ2 N:N′], [Cd(C7F5O2)2(C10H8N2)(H2O)2] n , (2), have been synthesized solvothermally and structurally characterized. Compound (1) shows a one-dimensional chain structure composed of Cd—O coordination bonds and is stabilized by π–π stacking and O—H...O hydrogen-bond interactions. Compound (2) displays a one-dimensional linear chain structure formed by Cd—N coordination interactions involving the 4,4′-bipyridine ligand. Adjacent one-dimensional chains are extended into two-dimensional sheets by O—H...O hydrogen bonds between the coordinated water molecules and adjacent carboxylate groups. Moreover, the chains are further linked by C—H...F—C interactions to afford a three-dimensional network. In both structures, hydrogen bonding involving the coordinated water molecules is a primary driving force in the formation of the supramolecular structures.

Diffraction of Electrons by Two and Three Mutually Orthogonal Standing Light Waves

1975 ◽  
Vol 53 (2) ◽  
pp. 157-164 ◽  
Author(s):  
F. Ehlotzky
Keyword(s):  
Electron Scattering ◽  
Light Wave ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Dimensional Problem ◽  
One Dimensional ◽  
Standing Light Wave ◽  
Light Waves ◽  
The One ◽  
Rectangular Lattices

The one-dimensional problem of electron scattering by a standing light wave, known as the Kapitza–Dirac effect, is shown to be easily extendable to two and three dimensions, thus showing all characteristics of diffraction of electrons by simple two- and three-dimensional rectangular lattices.

Two one-dimensional Ising models with disorder points

1970 ◽  
Vol 48 (14) ◽  
pp. 1724-1734 ◽  
Author(s):  
John Stephenson
Keyword(s):  
Temperature Dependence ◽  
Short Range ◽  
Short Range Order ◽  
Nearest Neighbor ◽  
Ising Models ◽  
Zero Field ◽  
Interaction Energies ◽  
Pair Correlations ◽  
One Dimensional ◽  
Range Of Values

Pair correlations on two one-dimensional Ising models with next-nearest-neighbor interactions are calculated exactly. For an appropriate range of values of the interaction energies, each of these models exhibits a disorder point, at which the nature of the short-range order changes abruptly, and at which there is a cusp in the graph of range of order vs. temperature. The zero-field susceptibilities are calculated exactly, and are found to have quite smooth temperature dependence.

Short-range ordering of vacancies and Fermi surface of TiO

1971 ◽  
Vol 27 (4) ◽  
pp. 376-383 ◽  
Author(s):  
J. R. Castles ◽  
J. M. Cowley ◽  
A. E. C. Spargo
Keyword(s):  
High Temperature ◽  
Fermi Surface ◽  
Diffuse Scattering ◽  
Short Range ◽  
Direct Relationship ◽  
Electronic Energy ◽  
High Temperature Phase ◽  
Titanium Monoxide ◽  
Temperature Phase ◽  
Short Range Ordering

The structure of the disordered (high-temperature) phase of titanium monoxide has been studied by electron diffraction. Composition-dependent complex distributions of diffuse scattering are observed and interpreted in terms of short-range-ordered configurations of lattice vacancies. The proposition that the form of the diffuse scattering may correspond to ordering under the influence of long-range electronic energy terms and so show a direct relationship to the topology of the Fermi surface is examined.

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