The superconducting transition temperatures and normal state residual electrical resistivities of the ternary Chevrel phase compounds Cu1.8Mo6S8-YSey (0 ≤y ≤ 8) and Cu1.8Mo6S8-y Tey (0 ≤ y ≤4) are reported. The data are examined for possible correlations with structural parameters of the rhombohedral unit call and the residual resistivity values. It is found that Tc decreases as the c/a ratio increases and as the rhombohedral angle approaches 90°. There is also an inverse correlation between Tc and the normal residual resistivity of the samples. © 1982.

Sankaranarayanan V

Department Of Physics

G. Rangarajan

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IIT Madras

Electrical resistivity and superconductivity in the chevrel phase compounds of the type Cu1.8Mo6S8—ySey (0 ⩽ y ⩽ 8) and Cu1.8Mo6S8—y Tey, (0 ⩽ y ⩽ 4)

Cryogenics

Absolute thermopower measurements on well oxygen annealed YBa2Cu3-xZnxO7-y (x=0.025, 0.05, 0.075, 0.1, 0.15, 0.2, 0.3, and 0.4) were made in the temperature range 250 K to the superconducting transition temperature, Tc (zero). X-ray analysis showed the specimens to be single phase. The Tc decreased drastically with increasing zinc concentration. The thermopower was found to be positive and an enhancement relative to the linear electron-diffusion contribution was observed over a range of temperatures from 125 K down to the onset of the superconducting transition temperature, Tc (onset). The enhancement showed a steep exponential drop as the temperature increases from Tc (onset). There exists unambiguous evidence that phonon drag is not responsible for the peak. The enhancement of thermopower in all these specimens varies more steeply with temperature than what one would expect from electron-phonon interaction. Hence, the cause of the enhancement must be other than the electron-phonon interaction. © 1989 The American Physical Society.

Physical Review B

Thermopower of zinc-doped Y-Ba-Cu-O

Normal-state electrical resistivity data from 12-300K on Chevrel-phase superconductors of the type Cu1.8Mo6S8-ySe y, 0&lt;or=y&lt;or=8, are reported. The temperature dependence of the normal-state resistivity has been analysed on the basis of models proposed for A15 superconductors. It is found that the 'parallel resistor' model based on s-d scattering accounts for the observed variation satisfactorily in most of the compounds, provided the lower limit of the transport theory integral is taken to have a non-zero value obtained by a fit to the experimental data. Physically, this limit corresponds to the minimum energy required for a phonon to scatter an electron from the s band into the d band. The electrical resistivity below 40K could also be interpreted on the basis of interband electron-electron scattering.

Journal of Physics F: Metal Physics

Normal-state electrical resistivity of Chevrel-phase superconductors of the type Cu1.8Mo6S8-ySey, 0≤y≤8

The thermoelectric power, S, of Chevrel-phase superconductors of the type Cu1.8Mo6S8-ySey, 0&lt;y&lt;8, and Cu1.8Mo6S8-yTey, 0&lt;y&lt;4, have been measured between 300K and the superconducting transition temperature. The high-temperature values are found to arise mainly from the diffusion of conduction electrons while at low temperatures phonon-drag contributions are also observed. The diffusion thermopower is interpreted in terms of Mott-Wilson theory and band-structure data. The phonon specific heat has also been measured in the case of Cu1.8Mo6S8 and Cu 1.8Mo6S1Se7 and is shown to be proportional to the phonon-drag part of the thermopower.

Thermoelectric power in the normal state of Chevrel-phase superconductors of the type Cu1.8Mo6S8-ySey, 0y8, and Cu1.8Mo6S8-yTey, 0y4

Journal of Applied Physics

Method for Measuring Electrical Resistivity of Anisotropic Materials

Journal of the Less Common Metals

The constitution diagram of the system Cux Mo6 S8 in the temperature range 11-2000 k

Journal of Low Temperature Physics

Resistivity and T c in disordered superconductors

Inorganic Chemistry

Relationship between superconductivity, magnetic susceptibility, and crystal structure in the pseudobinary system lead molybdenum sulfide-lead molybdenum selenide (PbMo6S8-PbMo6Se8)

Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry

Positional disorder and non-stoichiometry in Cu2−xMo3S4 compounds. II. The triclinic low-temperature structure of Cu0.9Mo3S4

Electrical resistivity and superconductivity in the chevrel phase compounds of the type Cu1.8Mo6S8-ySey (0 ≤ y ≤ 8) and Cu1.8Mo6S8-y Tey, (0 ≤ y ≤ 4)

Journal	Cryogenics
ISSN	00112275
Open Access	No