Non-Fermi-liquid behavior in UCu(4+x)Al(8-x) compounds
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
20/10/2012
20/10/2012
2011
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Resumo |
We report on experimental studies of the Kondo physics and the development of non-Fermi-liquid scaling in UCu(4+x)Al(8-x) family. We studied 7 different compounds with compositions between x = 0 and 2. We measured electrical transport (down to 65 mK) and thermoelectric power (down to 1.8 K) as a function of temperature, hydrostatic pressure, and/or magnetic field. Compounds with Cu content below x = 1.25 exhibit long-range antiferromagnetic order at low temperatures. Magnetic order is suppressed with increasing Cu content and our data indicate a possible quantum critical point at x(cr) approximate to 1.15. For compounds with higher Cu content, non-Fermi-liquid behavior is observed. Non-Fermi-liquid scaling is inferred from electrical resistivity results for the x = 1.25 and 1.5 compounds. For compounds with even higher Cu content, a sharp kink occurs in the resistivity data at low temperatures, and this may be indicative of another quantum critical point that occurs at higher Cu compositions. For the magnetically ordered compounds, hydrostatic pressure is found to increase the Neel temperature, which can be understood in terms of the Kondo physics. For the non-magnetic compounds, application of a magnetic field promotes a tendency toward Fermi-liquid behavior. Thermoelectric power was analyzed using a two-band Lorentzian model, and the results indicate one fairly narrow band (10 meV and below) and a second broad band (around hundred meV). The results imply that there are two relevant energy scales that need to be considered for the physics in this family of compounds. (C) 2011 Elsevier B.V. All rights reserved. National Science Foundation (NSF)[DMR 0804032] U.S. National Science Foundation (NSF) U.S. National Science Foundation (NSF) National Science Foundation (NSF)[DMR 0805335] US Department of Energy (DOE) U.S. Department of Energy (DOE) State of Florida State of Florida Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Brazil CNPq Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Brazil FAPESP |
Identificador |
PHYSICA B-CONDENSED MATTER, v.406, n.11, p.2061-2069, 2011 0921-4526 http://producao.usp.br/handle/BDPI/29407 10.1016/j.physb.2011.01.038 |
Idioma(s) |
eng |
Publicador |
ELSEVIER SCIENCE BV |
Relação |
Physica B-condensed Matter |
Direitos |
restrictedAccess Copyright ELSEVIER SCIENCE BV |
Palavras-Chave | #Non-Fermi-liquid scaling #Antiferromagnetic correlations #Quantum critical point #INTERMETALLIC COMPOUNDS #THERMOELECTRIC-POWER #HEAVY FERMIONS #TEMPERATURE #URANIUM #ALLOY #PHASE #Physics, Condensed Matter |
Tipo |
article original article publishedVersion |