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Title: Upper critical magnetic field of the heavy-electron superconductors U sub 1 minus x Th sub x Be sub 13 ( x =0 and 2. 9%) doped with paramagnetic Gd and other rare-earth ions

Abstract

The temperature {ital T} dependence of the upper critical magnetic field {ital H}{sub {ital c}2} of the heavy-electron superconductors U{sub 1{minus}{ital x}}Th{sub {ital x}}Be{sub 13} ({ital x}=0 and 2.9%) doped with various concentrations of Gd has been determined from low-frequency ac magnetic susceptibility measurements in magnetic fields up to 60 kOe. The {ital H}{sub {ital c}2}({ital T}) curves for U{sub 1{minus}{ital x}}Gd{sub {ital x}}Be{sub 13} samples deviate from the {ital H}{sub {ital c}2}({ital T}) curves of UBe{sub 13} near {ital T}{sub {ital c}}, which is consistant with the depairing of superconducting electrons via the Zeeman interaction between the spins of the superconducting electrons and the exchange field associated with the Gd spins. This suggests that UBe{sub 13} exhibits singlet superconductivity. In contrast, the {ital H}{sub {ital c}2}({ital T}) curves for (U{sub 0.97}Th{sub 0.03})Be{sub 13} doped with Gd scale with {ital H}{sub {ital c}2}({ital T}) of pure (U{sub 0.97}Th{sub 0.03})Be{sub 13} and do not reflect superconducting depairing by the Gd ions. These results are consistent with either strong spin-orbit scattering due to the presence of Th in UBe{sub 13}, or to a qualitatively different type of superconductivity involving triplet spin pairing in (U{sub 0.97}Th{sub 0.03})Be{sub 13}. Measurements of the temperature dependencemore » of {ital H}{sub {ital c}2} for U{sub 1{minus}{ital x}R{ital x}}Be{sub 13} compounds where {ital R}=La, Lu, and Ce for various compositions {ital x} as well as U{sub 0.985}{ital R0.015}Be{sub 13} compounds for {ital R}=Tb, Dy, Ho, and Er are also presented and compared with the Gd-doped UBe{sub 13} system. The results of low-temperature specific-heat measurements of UBe{sub 13} doped with various concentrations of Gd are also discussed.« less

Authors:
; ; ;  [1]; ;  [2]
  1. Department of Physics and Institute for Pure and Applied Physical Sciences, University of California, San Diego, La Jolla, California 92093 (US)
  2. Los Alamos National Laboratory, Los Alamos, New Mexico (USA)
Publication Date:
OSTI Identifier:
6115461
DOE Contract Number:  
FG03-86ER45230
Resource Type:
Journal Article
Journal Name:
Physical Review, B: Condensed Matter; (USA)
Additional Journal Information:
Journal Volume: 43:1; Journal ID: ISSN 0163-1829
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BERYLLIUM BASE ALLOYS; CRITICAL FIELD; THORIUM ALLOYS; URANIUM ALLOYS; GADOLINIUM ADDITIONS; RARE EARTH ADDITIONS; SPECIFIC HEAT; SUPERCONDUCTIVITY; TEMPERATURE DEPENDENCE; ULTRALOW TEMPERATURE; ZEEMAN EFFECT; ACTINIDE ALLOYS; ALLOYS; BERYLLIUM ALLOYS; ELECTRIC CONDUCTIVITY; ELECTRICAL PROPERTIES; GADOLINIUM ALLOYS; MAGNETIC FIELDS; PHYSICAL PROPERTIES; RARE EARTH ALLOYS; THERMODYNAMIC PROPERTIES; 360104* - Metals & Alloys- Physical Properties

Citation Formats

Dalichaouch, Y, Lee, B W, Lambert, S E, Maple, M B, Smith, J L, and Fisk, Z. Upper critical magnetic field of the heavy-electron superconductors U sub 1 minus x Th sub x Be sub 13 ( x =0 and 2. 9%) doped with paramagnetic Gd and other rare-earth ions. United States: N. p., 1991. Web. doi:10.1103/PhysRevB.43.299.
Dalichaouch, Y, Lee, B W, Lambert, S E, Maple, M B, Smith, J L, & Fisk, Z. Upper critical magnetic field of the heavy-electron superconductors U sub 1 minus x Th sub x Be sub 13 ( x =0 and 2. 9%) doped with paramagnetic Gd and other rare-earth ions. United States. doi:10.1103/PhysRevB.43.299.
Dalichaouch, Y, Lee, B W, Lambert, S E, Maple, M B, Smith, J L, and Fisk, Z. Tue . "Upper critical magnetic field of the heavy-electron superconductors U sub 1 minus x Th sub x Be sub 13 ( x =0 and 2. 9%) doped with paramagnetic Gd and other rare-earth ions". United States. doi:10.1103/PhysRevB.43.299.
@article{osti_6115461,
title = {Upper critical magnetic field of the heavy-electron superconductors U sub 1 minus x Th sub x Be sub 13 ( x =0 and 2. 9%) doped with paramagnetic Gd and other rare-earth ions},
author = {Dalichaouch, Y and Lee, B W and Lambert, S E and Maple, M B and Smith, J L and Fisk, Z},
abstractNote = {The temperature {ital T} dependence of the upper critical magnetic field {ital H}{sub {ital c}2} of the heavy-electron superconductors U{sub 1{minus}{ital x}}Th{sub {ital x}}Be{sub 13} ({ital x}=0 and 2.9%) doped with various concentrations of Gd has been determined from low-frequency ac magnetic susceptibility measurements in magnetic fields up to 60 kOe. The {ital H}{sub {ital c}2}({ital T}) curves for U{sub 1{minus}{ital x}}Gd{sub {ital x}}Be{sub 13} samples deviate from the {ital H}{sub {ital c}2}({ital T}) curves of UBe{sub 13} near {ital T}{sub {ital c}}, which is consistant with the depairing of superconducting electrons via the Zeeman interaction between the spins of the superconducting electrons and the exchange field associated with the Gd spins. This suggests that UBe{sub 13} exhibits singlet superconductivity. In contrast, the {ital H}{sub {ital c}2}({ital T}) curves for (U{sub 0.97}Th{sub 0.03})Be{sub 13} doped with Gd scale with {ital H}{sub {ital c}2}({ital T}) of pure (U{sub 0.97}Th{sub 0.03})Be{sub 13} and do not reflect superconducting depairing by the Gd ions. These results are consistent with either strong spin-orbit scattering due to the presence of Th in UBe{sub 13}, or to a qualitatively different type of superconductivity involving triplet spin pairing in (U{sub 0.97}Th{sub 0.03})Be{sub 13}. Measurements of the temperature dependence of {ital H}{sub {ital c}2} for U{sub 1{minus}{ital x}R{ital x}}Be{sub 13} compounds where {ital R}=La, Lu, and Ce for various compositions {ital x} as well as U{sub 0.985}{ital R0.015}Be{sub 13} compounds for {ital R}=Tb, Dy, Ho, and Er are also presented and compared with the Gd-doped UBe{sub 13} system. The results of low-temperature specific-heat measurements of UBe{sub 13} doped with various concentrations of Gd are also discussed.},
doi = {10.1103/PhysRevB.43.299},
journal = {Physical Review, B: Condensed Matter; (USA)},
issn = {0163-1829},
number = ,
volume = 43:1,
place = {United States},
year = {1991},
month = {1}
}