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Title: Upper critical fields in liquid-quenched metastable superconductors

Abstract

A systematic and quantitative study of upper critical fields in alloys with increasing atomic number is carried out. The alloys are prepared by the technique of liquid (splat) quenching. They include the metastable body-centered-cubic (..beta..) phase of Ti-Pd, Zr-Mo, Zr-Pd, and Hf-Mo, amorphous phase of Zr-Rh, and the stable ..beta.. phase of Ti-Mo and Ta-Hf. Measurements are made in magnetic fields up to 90 kG and in temperatures down to 0.5 K. The results are analyzed within the framework of the dirty-limit theory of Werthamer, Helfand, Hohenberg, and Maki (WHHM). A least-squares fitting routine is performed using all the data (weighted equally) for a given sample. It is emphasized that the visual critical-field gradient near the transition temperature cannot be taken as the actual gradient in the presence of Pauli paramagnetic limitation. The main findings are the following: (i) Even without including renormalization corrections due to electron-phonon and electron-electron interactions, very good fits to the WHHM theory are obtained; (ii) critical-field data for all our samples (with minor exceptions in Hf-Mo)= are found to fall below or on the Maki curve (i.e., when the spin-orbit scattering parameter lambda/sub s.o./ goes to infinity); (iii) values of lambda/sub s.o./ are observed tomore » range from 0.28 to 2.51 for the 3d and 4d alloys; (iv) the spin-orbit scattering rates 1/tau/sub s.o./ are found to compare well with theoretical estimation using results from band-structure calculation. The effect of sample inhomogeneity on the value of lambda/sub s.o./ in Zr-Mo alloys is also illustrated.« less

Authors:
; ;
Publication Date:
Research Org.:
Department of Physics, University of Virginia, Charlottesville, Virginia 22901
OSTI Identifier:
6468546
Resource Type:
Journal Article
Journal Name:
Phys. Rev. B: Condens. Matter; (United States)
Additional Journal Information:
Journal Volume: 30:3
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; MOLYBDENUM ALLOYS; SUPERCONDUCTIVITY; TITANIUM ALLOYS; PALLADIUM ALLOYS; ZIRCONIUM ALLOYS; BINARY ALLOY SYSTEMS; CRITICAL FIELD; DATA ANALYSIS; GINZBURG-LANDAU THEORY; METASTABLE STATES; SUPERCONDUCTORS; TRANSITION ELEMENTS; ULTRALOW TEMPERATURE; ALLOY SYSTEMS; ALLOYS; ELECTRIC CONDUCTIVITY; ELECTRICAL PROPERTIES; ELEMENTS; ENERGY LEVELS; EXCITED STATES; MAGNETIC FIELDS; METALS; PHYSICAL PROPERTIES; PLATINUM METAL ALLOYS; 360104* - Metals & Alloys- Physical Properties; 656102 - Solid State Physics- Superconductivity- Acoustic, Electronic, Magnetic, Optical, & Thermal Phenomena- (-1987)

Citation Formats

Wong, K M, Cotts, E J, and Poon, S J. Upper critical fields in liquid-quenched metastable superconductors. United States: N. p., 1984. Web. doi:10.1103/PhysRevB.30.1253.
Wong, K M, Cotts, E J, & Poon, S J. Upper critical fields in liquid-quenched metastable superconductors. United States. https://doi.org/10.1103/PhysRevB.30.1253
Wong, K M, Cotts, E J, and Poon, S J. Wed . "Upper critical fields in liquid-quenched metastable superconductors". United States. https://doi.org/10.1103/PhysRevB.30.1253.
@article{osti_6468546,
title = {Upper critical fields in liquid-quenched metastable superconductors},
author = {Wong, K M and Cotts, E J and Poon, S J},
abstractNote = {A systematic and quantitative study of upper critical fields in alloys with increasing atomic number is carried out. The alloys are prepared by the technique of liquid (splat) quenching. They include the metastable body-centered-cubic (..beta..) phase of Ti-Pd, Zr-Mo, Zr-Pd, and Hf-Mo, amorphous phase of Zr-Rh, and the stable ..beta.. phase of Ti-Mo and Ta-Hf. Measurements are made in magnetic fields up to 90 kG and in temperatures down to 0.5 K. The results are analyzed within the framework of the dirty-limit theory of Werthamer, Helfand, Hohenberg, and Maki (WHHM). A least-squares fitting routine is performed using all the data (weighted equally) for a given sample. It is emphasized that the visual critical-field gradient near the transition temperature cannot be taken as the actual gradient in the presence of Pauli paramagnetic limitation. The main findings are the following: (i) Even without including renormalization corrections due to electron-phonon and electron-electron interactions, very good fits to the WHHM theory are obtained; (ii) critical-field data for all our samples (with minor exceptions in Hf-Mo)= are found to fall below or on the Maki curve (i.e., when the spin-orbit scattering parameter lambda/sub s.o./ goes to infinity); (iii) values of lambda/sub s.o./ are observed to range from 0.28 to 2.51 for the 3d and 4d alloys; (iv) the spin-orbit scattering rates 1/tau/sub s.o./ are found to compare well with theoretical estimation using results from band-structure calculation. The effect of sample inhomogeneity on the value of lambda/sub s.o./ in Zr-Mo alloys is also illustrated.},
doi = {10.1103/PhysRevB.30.1253},
url = {https://www.osti.gov/biblio/6468546}, journal = {Phys. Rev. B: Condens. Matter; (United States)},
number = ,
volume = 30:3,
place = {United States},
year = {1984},
month = {8}
}