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Title: Superconductivity in ternary rare earth transition metal silicides and germanides with the Sc/sub 5/Co/sub 4/Si/sub 10/-type structure

Abstract

Low temperature heat capacity measurements indicate the presence of a complicated phonon density of states in these structurally complex compounds. A better description of the phonon spectrum of the high-T/sub c/ materials, Sc/sub 5/Rh/sub 4/Si/sub 10/, Sc/sub 5/Ir/sub 4/Si/sub 10/, and Y/sub 5/Os/sub 4/Ge/sub 10/, is presented and discussed. The large values of ..delta..C/..gamma../sub n/T/sub c/ and the electron-phonon coupling constant for these high T/sub c/ compounds indicate that they are strong-coupled superconductors. Dc electrical resistivity measurements on these compounds show resistivity behaviors deviating from those exhibited by simple metals. The rho(T) data for Y/sub 5/Ir/sub 4/Si/sub 10/, Lu/sub 5/Rh/sub 4/Si/sub 10/, Lu/sub 5/Ir/sub 4/Si/sub 10/, and Y/sub 5/Os/sub 4/Ge/sub 10/, indicate anomalies. Static molar magnetic susceptibility measurements performed on these compounds indicate a small effective magnetic moment of 0.26 ..mu../sub B/ on the Co atom and anomalous behaviors in the Lu/sub 5/Rh/sub 4/Si/sub 10/, Lu/sub 5/Ir/sub 4/Si/sub 10/, Y/sub 5/Ir/sub 4/Si/sub 10/, Lu/sub 5/Ir/sub 4/Ge/sub 10/, and Y/sub 5/Rh/sub 4/Ge/sub 10/ data. The formation of a charge- or spin-density wave may be causing the anomalous behaviors in both resistivity and susceptibility. Upper critical magnetic field measurements were performed on Sc/sub 5/Co/sub 4/Si/sub 10/, Sc/sub 5/Rh/sub 4/Si/sub 10/, Sc/sub 5/Ir/submore » 4/Si/sub 10/, Lu/sub 5/Rh/sub 4/Si/sub 10/, Lu/sub 5/Ir/sub 4/Si/sub 10/, and Y/sub 5/Os/sub 4/Ge/sub 10/. Y/sub 5/Os/sub 4/Ge/sub 10/ exhibits very high values for (-dH/sub c2//dT)/sub Tc/ = 10.2 kOe/K and H/sub c2/(0) = 60.4 kOe. Comparing the value of (-dH/sub c2//dT)/sub Tc/ gained from the fit of the data to the WHH theory to the calculated (-dH/sub c2//dT)/sub Tc/ yields various degrees of agreement for these compounds. There seems to be little or no Pauli limiting and the spin-orbit effect appears to be negligible.« less

Authors:
Publication Date:
Research Org.:
Ames Lab., IA (USA)
OSTI Identifier:
5283948
Report Number(s):
IS-T-1215
ON: DE86015764
DOE Contract Number:  
W-7405-ENG-82
Resource Type:
Technical Report
Resource Relation:
Other Information: Thesis. Thesis submitted by Linda Sue Berg to Iowa State University
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; GERMANIUM ALLOYS; ELECTRIC CONDUCTIVITY; MAGNETIC SUSCEPTIBILITY; SUPERCONDUCTIVITY; IRIDIUM SILICIDES; LUTETIUM ALLOYS; LUTETIUM SILICIDES; OSMIUM ALLOYS; RHODIUM SILICIDES; SCANDIUM SILICIDES; YTTRIUM ALLOYS; COBALT SILICIDES; CRITICAL FIELD; PHONONS; SPECIFIC HEAT; ALLOYS; COBALT COMPOUNDS; ELECTRICAL PROPERTIES; IRIDIUM COMPOUNDS; LUTETIUM COMPOUNDS; MAGNETIC FIELDS; MAGNETIC PROPERTIES; PHYSICAL PROPERTIES; PLATINUM METAL ALLOYS; QUASI PARTICLES; RARE EARTH ALLOYS; RARE EARTH COMPOUNDS; REFRACTORY METAL COMPOUNDS; RHODIUM COMPOUNDS; SCANDIUM COMPOUNDS; SILICIDES; SILICON COMPOUNDS; THERMODYNAMIC PROPERTIES; TRANSITION ELEMENT COMPOUNDS; 360603* - Materials- Properties; 656102 - Solid State Physics- Superconductivity- Acoustic, Electronic, Magnetic, Optical, & Thermal Phenomena- (-1987)

Citation Formats

Berg, L S. Superconductivity in ternary rare earth transition metal silicides and germanides with the Sc/sub 5/Co/sub 4/Si/sub 10/-type structure. United States: N. p., 1986. Web.
Berg, L S. Superconductivity in ternary rare earth transition metal silicides and germanides with the Sc/sub 5/Co/sub 4/Si/sub 10/-type structure. United States.
Berg, L S. Fri . "Superconductivity in ternary rare earth transition metal silicides and germanides with the Sc/sub 5/Co/sub 4/Si/sub 10/-type structure". United States.
@article{osti_5283948,
title = {Superconductivity in ternary rare earth transition metal silicides and germanides with the Sc/sub 5/Co/sub 4/Si/sub 10/-type structure},
author = {Berg, L S},
abstractNote = {Low temperature heat capacity measurements indicate the presence of a complicated phonon density of states in these structurally complex compounds. A better description of the phonon spectrum of the high-T/sub c/ materials, Sc/sub 5/Rh/sub 4/Si/sub 10/, Sc/sub 5/Ir/sub 4/Si/sub 10/, and Y/sub 5/Os/sub 4/Ge/sub 10/, is presented and discussed. The large values of ..delta..C/..gamma../sub n/T/sub c/ and the electron-phonon coupling constant for these high T/sub c/ compounds indicate that they are strong-coupled superconductors. Dc electrical resistivity measurements on these compounds show resistivity behaviors deviating from those exhibited by simple metals. The rho(T) data for Y/sub 5/Ir/sub 4/Si/sub 10/, Lu/sub 5/Rh/sub 4/Si/sub 10/, Lu/sub 5/Ir/sub 4/Si/sub 10/, and Y/sub 5/Os/sub 4/Ge/sub 10/, indicate anomalies. Static molar magnetic susceptibility measurements performed on these compounds indicate a small effective magnetic moment of 0.26 ..mu../sub B/ on the Co atom and anomalous behaviors in the Lu/sub 5/Rh/sub 4/Si/sub 10/, Lu/sub 5/Ir/sub 4/Si/sub 10/, Y/sub 5/Ir/sub 4/Si/sub 10/, Lu/sub 5/Ir/sub 4/Ge/sub 10/, and Y/sub 5/Rh/sub 4/Ge/sub 10/ data. The formation of a charge- or spin-density wave may be causing the anomalous behaviors in both resistivity and susceptibility. Upper critical magnetic field measurements were performed on Sc/sub 5/Co/sub 4/Si/sub 10/, Sc/sub 5/Rh/sub 4/Si/sub 10/, Sc/sub 5/Ir/sub 4/Si/sub 10/, Lu/sub 5/Rh/sub 4/Si/sub 10/, Lu/sub 5/Ir/sub 4/Si/sub 10/, and Y/sub 5/Os/sub 4/Ge/sub 10/. Y/sub 5/Os/sub 4/Ge/sub 10/ exhibits very high values for (-dH/sub c2//dT)/sub Tc/ = 10.2 kOe/K and H/sub c2/(0) = 60.4 kOe. Comparing the value of (-dH/sub c2//dT)/sub Tc/ gained from the fit of the data to the WHH theory to the calculated (-dH/sub c2//dT)/sub Tc/ yields various degrees of agreement for these compounds. There seems to be little or no Pauli limiting and the spin-orbit effect appears to be negligible.},
doi = {},
url = {https://www.osti.gov/biblio/5283948}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1986},
month = {8}
}

Technical Report:
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