Superconductivity in ternary metallic glasses has been investigated using the model pseudopotential approach, which has been found quite successful in explaining superconductivity in metals, binary alloys and binary glasses. It is observed that this simple methodology successfully explains superconducting behaviour of ternary glasses without requiring the solution of Dirac equation for a many body problem or estimation of various interactions as required in ab-initio pseudopotential theory. In the present work superconducting state parameters of fourteen metallic glasses of (Ni-Zr)-M system (M----Ti, V, Co, Cu) have been determined in the BCS-Eliashberg-McMillan framework. It is observed that addition of V, Co, and Cu as the third element (M) to a binary metallic glass (Ni3a Zr67) causes the parameters A, To, a, and NoV to decrease, and Coulomb pseudopotential (#*) to increase with concentration of M, showing that the presence of third element (M) causes suppression of superconducting behaviour of the alloy. The decrease in Tr with increasing concentration of third element (M) may be attributed to the modifications in density of states at the Fermi level N(EF), and probable changes in the band structure of the alloy due to addition of the third element (M). Slight difference is noticed when Ti is added to the Ni33 Zr67 alloy. In this case Tc rises initially and then decreases with concentration of M, showing a peak at about x = 0.05. This indicates that on addition of Ti, 3d states grow near the Fermi level and hence contribute substantially to N(EF), favouring superconducting behaviour in this case. The present results for Tc show an excellent agreement with the experimental data. Quadratic Tc equations have been proposed, which provide successfully the Tr values of ternary metallic glasses under consideration.

The screening dependence of superconducting state parameters (λ, µ*, T c , α and N 0 V) of nine metallic glasses of the Cu-Zr system has been studied in the BCS-Eliashberg-McMillan framework by employing five forms of dielectric screening function in conjunction with Ashcroft's potential. It is observed that the electron-phonon coupling strength (λ) and transition temperature (T c ) are quite sensitive to the form of the dielectric screening, whereas the Coulomb pseudopotential (µ*), isotope effect exponent (α ) and effective interaction strength (N 0 V) show weak dependences on screening function. The RPA form of dielectric screening is observed to yield the best results for all the glasses of the Cu-Zr system studied in the present work. Present computations yield almost linear variation of T c with concentration x of Cu in the Cu-Zr system, which is in agreement with the experimental data. A linear T c equation is proposed by fitting the present results for RPA screening, which is in conformity with other results for the experimental data.

The superconducting state properties of the nine metallic glasses of Cu1−cZrc system have been investigated in the BCS–Eliashberg–McMillan framework by extending this theory to the binary metallic glasses. The values of superconducting state parameters, namely, the electron–phonon coupling strength (λ), Coulomb pseudopotential (μ*), transition temperature (Tc), isotope effect exponent (α) and interaction strength (NoV) of Cu–Zr metallic glasses in the range of Zr in Cu have been worked out using Ashcroft’s potential along with the RPA form of the dielectric screening. The present results for Tc show an excellent agreement with the experimental data. The values of Tc, α and NoV are found to decrease continuously with increase of the Cu concentration in Zr, showing that Zr rich Cu–Zr glasses are favoured materials for superconductivity.

In this work we investigated the electrical properties of rapidly quenched amorphous BixSb alloys in the temperature range of 1.2 K to 345 K. The resistance reveals that for a broad range of different compositions, including that for the topological insulator (TI), a superconducting state in the amorphous phase is present. After crystallization and annealing at an intermediate temperature, we found that in pure Bi and BixSb alloys with composition corresponding to the TI, the superconductivity persists, but the transition shifts to a lower temperature. The highest superconducting transition temperature was found for pure Bi and those TI’s, with a shift to low temperatures when the Sb content is increased. After annealing at a maximum temperature of T = 345 K, the samples are non-superconducting within the experimental range and the behavior changes from semiconducting-like for pure Bi, to metallic-like for pure Sb. Transition temperature of the amorphous BixSb alloys have been calculated in the BCS–Eliashberg–McMillan framework, modified for binary alloys. The results can explain the experimental results and show that amorphous BixSb exhibits a strong to intermediate electron–phonon coupling.

Lattice parameter and corresponding total free energy have been computed for cubic SrMO 3 perovskites (M = Ti, Zr, Mo, Rh, Ru) using the first principle approach within Density functional theory. The results have been calculated using local density approximation (LDA) method. It is found that the calculated lattice parameter for all transition metal oxides are in good agreement with the available experimental data. The total free energy corresponding to this lattice constant has been calculated along with different components of the total free energy. All these calculations have been carried out using ABINIT computer code.