# Electron transport in Chevrel phase superconductors, Cu1.8Mo6S8-y Se y , 0⩽y⩽8 and Cu1.8Mo6S8-y Te y , 0⩽y⩽4—Fit to Cote-Meisel theory

TL;DR: In this article, the normal state electrical resistivity of the Chevrel phase compounds of the type Cu1.8Mo6S8−ySey, 0⩽y8 and 0y 4 is analyzed on the basis of the generalized diffraction model which incorporates a postulate on electron-phonon interaction, viz phonons with wavelength exceeding the electron mean-free path are ineffective electron scatterers.

Abstract: Normal state electrical resistivity of the Chevrel phase compounds of the type Cu1.8Mo6S8−ySey, 0⩽y⩽8 and Cu1.8Mo6S8−yTey, 0⩽y⩽4 is analysed on the basis of the generalized diffraction model which incorporates a postulate on electron-phonon interaction,viz phonons with wavelength exceeding the electron mean-free path are ineffective electron scatterers. Fit obtained by this model was found to be superior to other models based on the interbands-d scattering of electrons.

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TL;DR: In this article, the influence of room-temperature annealing on the parameters of the basalplane electrical resistance of underdoped YBa$_2$Cu$_3$O$7-\delta$ and HoBa$-2$cu$_4$O $7- \delta} single crystals in the normal and superconducting states is investigated.

Abstract: The influence of room-temperature annealing on the parameters of the basal-plane electrical resistance of underdoped YBa$_2$Cu$_3$O$_{7-\delta}$ and HoBa$_2$Cu$_3$O$_{7-\delta}$ single crystals in the normal and superconducting states is investigated. The form of the derivatives $d\rho(T)/dT$ makes it possible to determine the onset temperature of the fluctuation conductivity and indicates a nonuniform distribution of the labile oxygen. Annealing has been revealed to lead to a monotonic decrease in the oxygen deficiency, that primarily manifests itself as a decrease of the residual resistance, an increase of $T_c$, and a decrease of the Debye temperature.

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TL;DR: In this paper, the influence of room-temperature annealing on the parameters of the basalplane electrical resistance of underdoped single crystals in the normal and superconducting states is investigated.

Abstract: The influence of room-temperature annealing on the parameters of the basal-plane electrical resistance of underdoped $$\hbox {YBa}_2\hbox {Cu}_3\hbox {O}_{7-\delta }$$
and $$\hbox {HoBa}_2\hbox {Cu}_3\hbox {O}_{7-\delta }$$
single crystals in the normal and superconducting states is investigated. The form of the derivatives $$\mathrm{d}\rho (T)/\mathrm{d}T$$
makes it possible to determine the onset temperature of the fluctuation conductivity and indicates a nonuniform distribution of the labile oxygen. Annealing has been revealed to lead to a monotonic decrease in the oxygen deficiency, that primarily manifests itself as a decrease in the residual resistance, an increase of $$T_c$$
, and a decrease in the Debye temperature.

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TL;DR: In this article, the electronic properties of liquid polyvalent metals are discussed in relation to the nearly free-electron model and the optical properties fit a simple Drude formula, with the same density of states as for free electrons.

Abstract: The electronic properties of liquid polyvalent metals are discussed in relation to the nearly-free-electron model. The observed Hall effect (including some new measurements on Hg, In and Sn) is consistent in most cases with a spherical Fermi surface for the valence electrons. The optical properties fit a simple Drude formula, with the same density of states as for free electrons. The evidence from the magnetic susceptibility and its change at the melting point is only qualitative, but is consistent with a free-electron sphere in the liquid. Only the observed small change in the Knight shift on melting is difficult to interpret in our model. As in I (Ziman 1961) the electrical resistivity is assumed to be represented, in first approximation, by an integral over the angle of scattering of a conduction electron, where the integrand contains the x-ray scattering function of the liquid and the Fourier transform of a ‘pseudo-potential’ for each ion. The formula adequately describes the data, with a pse...

393 citations

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TL;DR: The theory of electrical resistance developed by Bloch and others reats the conduction electrons as moving independently of one another but interacting with the lattice vibrations as discussed by the authors, and gives for the resistance of a metal, subject to certain simplifying assumptions, the formula R = const.

Abstract: The theory of electrical resistance developed by Bloch and others reats the conduction electrons as moving independently of one another but interacting with the lattice vibrations. The theory gives for the resistance of a metal, subject to certain simplifying assumptions, the formula R = const. G (ʘ/T) G ( x ) = 5/x5 ∫x o ξ4dξ/eξ-1 - 1/ex-1, (1) where ʘ is the Debye characteristic temperature. At low temperatures formula (1) leads to the conclusion that R varies as T5. The function G ( x ) was first proposed by Gruneisen.

209 citations

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TL;DR: The Evans modification of Ziman liquid-metal theory is extended to apply to amorphous and disordered crystalline alloys as mentioned in this paper, and the theory is shown to explain such common behavior of these systems as the change in sign of the temperature coefficient of resistivity with alloy composition.

Abstract: The Evans modification of Ziman liquid-metal theory is extended to apply to amorphous and disordered crystalline alloys. In particular, the theory is shown to explain such common behavior of these systems as the change in sign of the temperature coefficient of resistivity with alloy composition, the quadratic temperature dependence of resistivity at low temperature, and the linear temperature dependence of resistivity at high temperatures.

131 citations

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TL;DR: In this article, a generalized diffraction model was proposed to incorporate a postulate on the electron-phonon interaction; viz., phonons with wavelength exceeding the electron mean free path are ineffective electron scatterers.

Abstract: The diffraction model is generalized to incorporate a postulate on the electron-phonon interaction; viz., phonons with wavelength exceeding the electron mean free path are ineffective electron scatterers. This postulate leads to a limiting resistivity when the electron mean free path is of the order of the interatomic spacing. The generalized diffraction model is also shown to explain many anomalous features common to high-resistivity metals. Crystalline Nb, $A15'\mathrm{s}$, and glassy metals are discussed.

96 citations

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TL;DR: In this paper, the authors reported the results and interpretation of precision measurements of the electrical resistivity of the Si in the temperature range of 16.8$ K. They found that the resistivities of all the samples are well described by a temperature dependence of the form

Abstract: We report the results and interpretation of precision measurements of the electrical resistivity of ${\mathrm{V}}_{3}$Si in the temperature range ${T}_{c}\ensuremath{\le}T\ensuremath{\le}77$ K. Four samples of a wide range in residual resistance ratio (RRR) and with $15.1\ensuremath{\le}{T}_{c}\ensuremath{\le}16.8$ K have been investigated. We find that the resistivity of all the samples is well described by a temperature dependence of the form $\ensuremath{\rho}(T)={\ensuremath{\rho}}_{0}+b{T}^{n}+d\mathrm{exp}(\ensuremath{-}\frac{{T}_{0}}{T})$, where $n$ falls within the range $1\ensuremath{\le}n\ensuremath{\le}2$. The parameter $d$ is sensitive to the RRR of the sample, whereas $b$ and ${T}_{0}$ are relatively insensitive. The characteristic temperature ${T}_{0}\ensuremath{\approx}175$ K is essentially independent of the choice of $n$ within the stated range. A similar exponential term in $\ensuremath{\rho}(T)$ of ${\mathrm{Nb}}_{3}$Sn with ${T}_{0}\ensuremath{\approx}85$ K has previously been identified by Woodard and Cody. Nothing that in both ${\mathrm{V}}_{3}$Si and ${\mathrm{Nb}}_{3}$Sn the value of ${T}_{0}$ corresponds to the energy of [100] TA phonons near the zone boundary, we argue that the exponential term is due either to phonon-assisted interband scattering or intraband umklapp scattering. The reasons for the scattering effectiveness of this phonon will be discussed in light of recent band-structure calculations by Mattheiss and previous band models proposed to explain the anomalous normal-state properties of $A\ensuremath{-}15$ compounds. The nonexponential term in the resistivity is more difficult to characterize empirically and its origin is correspondingly more uncertain. We suggest it arises from intraband electron-electron scattering. The temperature dependence of the resistivity will be discussed with respect to anomalies observed in the low-temperature elastic constants, magnetic susceptibility, and specific heat of ${\mathrm{V}}_{3}$Si.

46 citations