A pseudopotential approach to the superconducting state properties of metallic glass

Abstract

The superconducting state properties of the metallic glass Ca 70 Mg 30 have been investigated in the BCS-Eliashberg-McMillan framework by extending this theory to the binary metal glasses. Pseudo ions with average properties have been considered to replace both types of ions in the system. Values of the superconducting state parameters, namely electron-phonon coupling strength (λ), Coloumb pseudopotential (µ * ), transition temperature (T c ), isotope effect exponent (α) and interaction strength (N 0 V ) have been worked out using Ashcroft's potential and the linear potential due to Sharma and Kachhava along with six different forms of dielectric screening. The form factors directly obtained from the screened pseudopotential of Veljkovic and Slavic have also been used to explicitly observe the effect of the dielectric screening on T c , α and N 0 V through µ * . The results obtained established the presence of a superconducting phase in Ca 70 Mg 30 glass.

A pseudopotential approach to the superconducting state parameters of (Ni33Zr67)1−x M x (M=Ti, V, Co, Cu) ternary metallic glasses

“…In this paper we have investigated superconducting state parameters of fourteen ternary metallic glasses of (Ni-Zr)-M system by extending the model pseudopotential technique [5] of binary metallic glasses to the ternary systems.…”

Superconducting state parameters of binary metallic glasses

“…The Ashcroft's empty core (EMC) model potential is a simple one-parameter model potential [28], which has been successfully found for various metallic complexes [5][6][7][8][9][10][11][12][13][14][15][18][19][20][21][22][23][24][25][26][27]. When used with a suitable form of dielectric screening functions, this potential has also been found to yield good results in computing the SSPs of metallic glasses [5][6][7][8][9][10][11][12][13][14][15][18][19][20][21][22][23][24][25][26][27] 25 metallic glass, the model potential parameter C is fitted with the experimental data of the electron-phonon coupling strength λ, which came from the experimental tunneling data [37]. After fitting the model potential parameter C , same C is then used in the computation of the SSPs of binary metallic glasses.…”

“…Experiments also show that the superconducting transition temperature T C is grater for amorphous metals than for crystals, which also depends on the composition of the metallic element in the crystalline as well as amorphous phases . Though the pseudo-potential theory is found very successful in studying the various properties of metallic glasses, there have been very few random attempts to study the superconducting state parameters (SSPs) of binary metallic glasses based on model potential [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27]. The application of a pseudo-potential to a binary metallic glass involves the assumption of pseudoions with average properties, which are assumed to replace two types of ions in the binary systems.…”

“…They have used Ashcroft's empty core (EMC) model potential [28] in the computation of the SSPs. The screening dependence of the SSPs of Ca 70 Mg 30 metallic glass has been studied by Sharma and Sharma [27] using Ashcroft's empty core (EMC) model potential [28], Sharma and Kachhava's linear potential [29] and Veljkovic and Slavic [30] model potential. The theoretical investigation of the SSPs of Cu-Zr metallic glasses has been reported by Sharma et al.…”

Superconducting state parameters of La100-C GaC binary metallic glasses

“…In most of the above mentioned studies on SSP of binary metallic glasses [20][21][22][23][24][25][26][27][28][29], the Vegard's law was used to calculate electron-ion interaction from the potential of the pure components. Also in metallic glasses, the translational symmetry is broken, and therefore, the momentum (or quasi-momentum) should not be used to describe the state of the system.…”