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Title: Upper critical fields and superconducting transition temperatures of some zirconium-base amorphous transition-metal alloys

Abstract

Superconducting upper critical fields H/sub c/2(T), transition temperatures T/sub c/, and normal-state electrical resistivities rho/sub n/ have been measured in the amorphous transition-metal alloy series Zr/sub 1-z/Co/sub x/, Zr/sub 1-x/Ni/sub x/, (Zr/sub 1-x/Ti/sub x/)/sub 0.78/Ni/sub 0.22/, and (Zr/sub 1-x/Nb/sub x/)/sub 0.78/Ni/sub 0.22/. Structural integrity of these melt-spun alloys is indicated by x-ray, density, bend-ductility, normal-state electrical resistivity, superconducting transition width, and mixed-state flux-pinning measurements. The specimens display T/sub c/ = 2.1--3.8 K, rho/sub n/ = 159--190 ..mu cap omega.. cm, and Vertical Bar(dH/sub c/2/dT)cVertical Bar = 28--36 kG/K. These imply electron mean free paths lroughly-equal2--6 A, zero-temperature Ginzburg-Landau coherence distances xi/sub G/0roughly-equal50--70 A, penetration depths lambda/sub G/0roughly-equal(7--10) x 10/sup 3/ A, and extremely high dirtiness parameters xi/sub 0//lroughly-equal300--1300. All alloys display H/sub c/2(T) curves with negative curvature and (with two exceptions) fair agreement with the standard dirty-limit theory of Werthamer, Helfand, Hohenberg, and Maki (WHHM) for physically reasonable values of spin-orbit-coupling induced, electron-spin-flip scattering time tau/sub so/. This is in contrast to the anomalously elevated H/sub c/2(T) behavior which is nearly linear in T that is observed by some, and the unphysically low-tau/sub so/ fits to WHHM theory obtained by others, for various amorphous alloys.

Authors:
;
Publication Date:
Research Org.:
Department of Physics, Indiana University, Bloomington, Indiana 47405
OSTI Identifier:
5655635
Resource Type:
Journal Article
Journal Name:
Phys. Rev. B: Condens. Matter; (United States)
Additional Journal Information:
Journal Volume: 28:3
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; COBALT ALLOYS; SUPERCONDUCTIVITY; NICKEL ALLOYS; NIOBIUM ALLOYS; TITANIUM ALLOYS; ZIRCONIUM BASE ALLOYS; CRITICAL FIELD; ELECTRIC CONDUCTIVITY; EXPERIMENTAL DATA; TEMPERATURE COEFFICIENT; TEMPERATURE DEPENDENCE; TRANSITION TEMPERATURE; ALLOYS; DATA; ELECTRICAL PROPERTIES; INFORMATION; MAGNETIC FIELDS; NUMERICAL DATA; PHYSICAL PROPERTIES; REACTIVITY COEFFICIENTS; THERMODYNAMIC PROPERTIES; ZIRCONIUM ALLOYS; 360104* - Metals & Alloys- Physical Properties; 656102 - Solid State Physics- Superconductivity- Acoustic, Electronic, Magnetic, Optical, & Thermal Phenomena- (-1987)

Citation Formats

Karkut, M G, and Hake, R R. Upper critical fields and superconducting transition temperatures of some zirconium-base amorphous transition-metal alloys. United States: N. p., 1983. Web. doi:10.1103/PhysRevB.28.1396.
Karkut, M G, & Hake, R R. Upper critical fields and superconducting transition temperatures of some zirconium-base amorphous transition-metal alloys. United States. doi:10.1103/PhysRevB.28.1396.
Karkut, M G, and Hake, R R. Mon . "Upper critical fields and superconducting transition temperatures of some zirconium-base amorphous transition-metal alloys". United States. doi:10.1103/PhysRevB.28.1396.
@article{osti_5655635,
title = {Upper critical fields and superconducting transition temperatures of some zirconium-base amorphous transition-metal alloys},
author = {Karkut, M G and Hake, R R},
abstractNote = {Superconducting upper critical fields H/sub c/2(T), transition temperatures T/sub c/, and normal-state electrical resistivities rho/sub n/ have been measured in the amorphous transition-metal alloy series Zr/sub 1-z/Co/sub x/, Zr/sub 1-x/Ni/sub x/, (Zr/sub 1-x/Ti/sub x/)/sub 0.78/Ni/sub 0.22/, and (Zr/sub 1-x/Nb/sub x/)/sub 0.78/Ni/sub 0.22/. Structural integrity of these melt-spun alloys is indicated by x-ray, density, bend-ductility, normal-state electrical resistivity, superconducting transition width, and mixed-state flux-pinning measurements. The specimens display T/sub c/ = 2.1--3.8 K, rho/sub n/ = 159--190 ..mu cap omega.. cm, and Vertical Bar(dH/sub c/2/dT)cVertical Bar = 28--36 kG/K. These imply electron mean free paths lroughly-equal2--6 A, zero-temperature Ginzburg-Landau coherence distances xi/sub G/0roughly-equal50--70 A, penetration depths lambda/sub G/0roughly-equal(7--10) x 10/sup 3/ A, and extremely high dirtiness parameters xi/sub 0//lroughly-equal300--1300. All alloys display H/sub c/2(T) curves with negative curvature and (with two exceptions) fair agreement with the standard dirty-limit theory of Werthamer, Helfand, Hohenberg, and Maki (WHHM) for physically reasonable values of spin-orbit-coupling induced, electron-spin-flip scattering time tau/sub so/. This is in contrast to the anomalously elevated H/sub c/2(T) behavior which is nearly linear in T that is observed by some, and the unphysically low-tau/sub so/ fits to WHHM theory obtained by others, for various amorphous alloys.},
doi = {10.1103/PhysRevB.28.1396},
journal = {Phys. Rev. B: Condens. Matter; (United States)},
number = ,
volume = 28:3,
place = {United States},
year = {1983},
month = {8}
}