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Title: Connections between magnetism and superconductivity in UBe sub 13 doped with thorium or boron (invited)

Abstract

Magnetism and superconductivity appear to be intimately connected in the heavy electron (HE) superconductors. For example, it has been conjectured but not proven that the exchange of antiferromagnetic spin fluctuations are responsible for pairing in HE superconductors. In this paper we review recent results in U{sub 1{minus}{ital x}}Th{sub {ital x}}Be{sub 13}, where specific heat, lower critical field, and zero-field muon-spin-resonance ({mu}SR) measurements reveal another second-order phase transition (below the superconducting transition) to a state which possesses small-moment magnetic correlations for 0.019{le}{ital x}{le}0.043. We present a new phase diagram for (U,Th)Be{sub 13} which indicates that the superconducting and magnetic order parameters are closely coupled. A discussion of the nature of the lower phase is presented, including the consideration of a possible magnetic (time-reversal-violating) superconducting state. When UBe{sub 13} is doped with B (UBe{sub 12.97}B{sub 0.03}) the Kondo temperature is decreased and the specific heat jump at the superconducting transition temperature is significantly enhanced. However, {mu}SR measurements reveal no magnetic signature in UBe{sub 12.97}B{sub 0.03}, unlike the case for Th doping. The correlation between changes in the Kondo temperature and changes in the superconducting properties induced by B doping provide evidence for the importance of magnetic excitations in the superconducting pairing interactionmore » in UBe{sub 13}.« less

Authors:
 [1]; ;  [2];  [3];  [4]
  1. Los Alamos National Laboratory, Los Alamos, New Mexico (USA)
  2. ETH, Zurich c/o PSI, CH 5232, Villigen (Switzerland)
  3. Kamerlingh Onnes Laboratory, 2300 RA Leiden (The Netherlands)
  4. U. C. Riverside, Riverside (California 92521-04131)
Publication Date:
OSTI Identifier:
5125883
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics; (United States)
Additional Journal Information:
Journal Volume: 70:10; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; BERYLLIUM ALLOYS; SUPERCONDUCTIVITY; URANIUM ALLOYS; BORON ADDITIONS; COMPARATIVE EVALUATIONS; CRITICAL FIELD; KONDO EFFECT; MAGNETISM; MUON SPIN RELAXATION; PHASE DIAGRAMS; PHASE TRANSFORMATIONS; SPECIFIC HEAT; THORIUM ADDITIONS; ACTINIDE ALLOYS; ALLOYS; BORON ALLOYS; DIAGRAMS; ELECTRIC CONDUCTIVITY; ELECTRICAL PROPERTIES; EVALUATION; MAGNETIC FIELDS; PHYSICAL PROPERTIES; RELAXATION; THERMODYNAMIC PROPERTIES; THORIUM ALLOYS; 360104* - Metals & Alloys- Physical Properties; 656100 - Condensed Matter Physics- Superconductivity

Citation Formats

Heffner, R H, Ott, H R, Schenck, A, Mydosh, J A, and MacLaughlin, D E. Connections between magnetism and superconductivity in UBe sub 13 doped with thorium or boron (invited). United States: N. p., 1991. Web. doi:10.1063/1.350160.
Heffner, R H, Ott, H R, Schenck, A, Mydosh, J A, & MacLaughlin, D E. Connections between magnetism and superconductivity in UBe sub 13 doped with thorium or boron (invited). United States. doi:10.1063/1.350160.
Heffner, R H, Ott, H R, Schenck, A, Mydosh, J A, and MacLaughlin, D E. Fri . "Connections between magnetism and superconductivity in UBe sub 13 doped with thorium or boron (invited)". United States. doi:10.1063/1.350160.
@article{osti_5125883,
title = {Connections between magnetism and superconductivity in UBe sub 13 doped with thorium or boron (invited)},
author = {Heffner, R H and Ott, H R and Schenck, A and Mydosh, J A and MacLaughlin, D E},
abstractNote = {Magnetism and superconductivity appear to be intimately connected in the heavy electron (HE) superconductors. For example, it has been conjectured but not proven that the exchange of antiferromagnetic spin fluctuations are responsible for pairing in HE superconductors. In this paper we review recent results in U{sub 1{minus}{ital x}}Th{sub {ital x}}Be{sub 13}, where specific heat, lower critical field, and zero-field muon-spin-resonance ({mu}SR) measurements reveal another second-order phase transition (below the superconducting transition) to a state which possesses small-moment magnetic correlations for 0.019{le}{ital x}{le}0.043. We present a new phase diagram for (U,Th)Be{sub 13} which indicates that the superconducting and magnetic order parameters are closely coupled. A discussion of the nature of the lower phase is presented, including the consideration of a possible magnetic (time-reversal-violating) superconducting state. When UBe{sub 13} is doped with B (UBe{sub 12.97}B{sub 0.03}) the Kondo temperature is decreased and the specific heat jump at the superconducting transition temperature is significantly enhanced. However, {mu}SR measurements reveal no magnetic signature in UBe{sub 12.97}B{sub 0.03}, unlike the case for Th doping. The correlation between changes in the Kondo temperature and changes in the superconducting properties induced by B doping provide evidence for the importance of magnetic excitations in the superconducting pairing interaction in UBe{sub 13}.},
doi = {10.1063/1.350160},
journal = {Journal of Applied Physics; (United States)},
issn = {0021-8979},
number = ,
volume = 70:10,
place = {United States},
year = {1991},
month = {11}
}