A pseudopotential approach to the superconducting state parameters of (Ni33Zr67)1? x M x (M=Ti, V, Co, Cu) ternary metallic glasses |
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Authors: | Smita Sharma Haniph Khan and K S Sharma |
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Institution: | (1) Department of Physics, Government Dungar College, 334 001 Bikaner, Rajasthan, India;(2) Department of Physics, MSJ Government College, 321 001 Bharatpur, Rajasthan, India;(3) University of Kota, 324 001 Kota, Rajasthan, India |
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Abstract: | 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 (Ni33 Zr67) causes the parameters λ,T
c, α, andN
0
V to decrease, and Coulomb pseudopotential (μ*) to increase with concentration of M, showing that the presence of third element (M) causes suppression of superconducting
behaviour of the alloy. The decrease inT
c with increasing concentration of third element (M) may be attributed to the modifications in density of states at the Fermi
levelN(E
F), 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 caseT
c rises initially and then decreases with concentration of M, showing a peak at aboutx=0.05. This indicates that on addition of Ti, 3d states grow near the Fermi level and hence contribute substantially toN(E
F), favouring superconducting behaviour in this case. The present results forT
c show an excellent agreement with the experimental data. QuadraticT
c equations have been proposed, which provide successfully theT
c values of ternary metallic glasses under consideration.
Paper presented at National Conference on Current Trends in Condensed Matter Research, Warangal, India, September 20–22, 2004. |
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Keywords: | 61 43 Fs 71 15 Dx 74 20 -z 74 70 Dd |
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