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Author (up) Besnus, M.J.; Kappler, J.P.; Ravet, M.F.; Meyer, A.; Lahiouel, R.; Pierre, J.; Siaud, E.; Nieva, G.L.; Sereni, J.G.
Title Structural and magnetic properties of the ternary rare earth (RE) compound series REInAu2(RE~La to Lu, Y) Type Journal Article
Year 1986 Publication Journal of the less-common metals Abbreviated Journal
Volume 120 Issue 1 Pages 101-112
Keywords
Abstract Results of structural, magnetic and heat capacity studies are reported for the REInAu2 series (except europium). A crystallographic transformation from cubic to tetragonal structure occurs for the compounds with lanthanum, cerium, praseodymium and neodymium. With the exception of LaInAu2, the phase transition has no observable effect on the magnetic susceptibility. Compounds formed with gadolinium, terbium, dysprosium and holmium order antiferromagnetically at low temperature. In this series YbInAu2 is confirmed to be in an unstable valence state with the maximum 2J + 1 = 8 ground state degeneracy.
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ISSN 0022-5088 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number BT @ gnieva @ Serial 424
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Author (up) Braun, E.; Bürger, A.; Nieva, G.L.; Roden, B.; Sereni, J.G.
Title Unexpected magnetic behaviour in a singlet crystal field ground state induced by Tb 4f-instability Type Journal Article
Year 1988 Publication Zeitschrift für Physik B Condensed Matter Abbreviated Journal Z. Phys. B
Volume 70 Issue 2 Pages 187-192
Keywords
Abstract The magnetic susceptibility (chi) of Th1-x Tb x alloys (with 5<x<55a/o Tb) in the range of 1 K<T<350K and the specific heat (forx=1.5a/o Tb) for 0.5<T<10 K were measured. A maximum in chi(T) was observed at a temperature which depends on concentration. The crystal field level scheme that fits the specific heat measurements shows two non-magnetic singlets as lowest levels. Such ambiguity is discussed within the framework of the 4f-Tb instability. The results are in agreement with the matrix superconductiveT c decrease. The contribution of the interconfigurational mixing on chi and the specific heat is also discussed.
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Corporate Author Thesis
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0722-3277 ISBN Medium
Area Expedition Conference
Notes ISI:A1988M112900009 Approved no
Call Number BT @ hernan @ Serial 127
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Author (up) NIEVA, G.L.; SERENI, J.G.; AFYOUNI, M.; SCHMERBER, G.; KAPPLER, J.P.
Title FROM FERROMAGNETIC TO NON-MAGNETIC SINGLET GROUND-STATE IN CEPD1-XNIX Type Journal Article
Year 1988 Publication Zeitschrift für Physik B Condensed Matter Abbreviated Journal Z. Phys. B
Volume 70 Issue 2 Pages 181-186
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0722-3277 ISBN Medium
Area Expedition Conference
Notes ISI:A1988M112900008 Approved no
Call Number BT @ hernan @ Serial 126
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Author (up) Safar, H.; Gammel, P.L.; Huse, D.A.; Majumdar, S.N.; Schneemeyer, L.F.; Bishop, D.J.; Lopez, D.; Nieva, G.L.; de la Cruz, F.
Title Observation of a nonlocal conductivity in the mixed state of YBa2Cu3O7-d: Experimental evidence for a vortex line liquid Type Journal Article
Year 1994 Publication Physical Review Letters Abbreviated Journal Phys. Rev. Lett.
Volume 72 Issue 8 Pages 1272
Keywords
Abstract We report on transport measurements in the mixed state of YBa2Cu3O7 single crystals using the dc flux transformer geometry. In the vortex fluid regime we have observed the onset of a nonlocal conductivity. At lower temperatures, close to but above the phase transition temperature the vortices become effectively three dimensional in character. This is in sharp contrast to recent flux transformer experiments on Bi2Sr2CaCu2O which have failed to see a nonlocal conductivity, confirming the two-dimensional character at high temperatures of the vortices in that system. These observations suggest that in a finite temperature interval, the vortex state in YBa2Cu3O7 is a line liquid.
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Notes Approved no
Call Number BT @ gnieva @ Serial 443
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Author (up) Sereni, J.G.; Nieva, G.L.; Schmerber, G.; Kappler, J.P.
Title EVIDENCES FOR UNCONVENTIONAL SUPERCONDUCTIVITY IN RARE-EARTH INTERMETALLICS Type Journal Article
Year 1989 Publication Modern Physics Letters B Abbreviated Journal Mod. Phys. Lett. B
Volume 3 Issue 16 Pages 1225-1231
Keywords
Abstract The specific heat of CeRu2 and La5Rh4 of the superconducting state does not follow a BCS-exponential temperature dependence, but a T2 law. At very low temperature (T = 0.1 Tc), CeRu2 shows a linear T dependence, which corresponds to a constant density of states. The experimental results are well described by the theoretical predictions for an axial state (CeRu2) and polar state (La5Rh4) superconductors. The small Sommerfeld coefficient of La5Rh4(? = 3.4 mJ/K2 La at.) excludes this compound from the heavy fermion superconductors.
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Notes Approved no
Call Number BT @ gnieva @ Serial 428
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Author (up) SERENI, J.G.; NIEVA, G.L.; HUBER, J.G.; DELONG, L.E.
Title LOW-TEMPERATURE SPECIFIC-HEAT OF THE TH-7(FE,CO,NI)(3) PSEUDOBINARY SUPERCONDUCTORS Type Journal Article
Year 1994 Publication PHYSICA C Abbreviated Journal
Volume 230 Issue 1-2 Pages 159-162
Keywords
Abstract Low-temperature specific heat (C-p) of the superconducting Th-7(Fe1-xCox)(3) and Th-7(Fe1-xNix)(3) intermetallic compounds is reported. In the normal state, the Sommerfeld coefficient (y), the Debye temperature and the electron-phonon coupling constant are found to be very similar to those of the pure Th. The superconducting phase exhibits a BCS-type behavior, as it is indicated by the exponential Cp vs. T dependence, and the Delta Cp/yT(c), = 1.48 ratio, where Delta Cp is the Cp(T)jump at the transition temperature (T-c).
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4534 ISBN Medium
Area Expedition Conference
Notes ISI:A1994PE88400019 Approved no
Call Number BT @ hernan @ Serial 102
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Author (up) Sereni, J.G.; Nieva, G.L.; Olcese, G.L.; Herr, A.; Kappler, J.P.
Title Ce3In: A cerium concentrated heavy fermion Type Journal Article
Year 1991 Publication Physica B: Condensed Matter Abbreviated Journal Physica B
Volume 171 Issue 1-4 Pages 335-339
Keywords
Abstract The fcc-Ce3In compound is presented as the best available approximation to reproduce the main magnetic properties of gamma-Ce at low temperatures, where such a pure phase does not exist. The electronic specific heat shows a maximum at 18 K and an anomaly at 2.2 K, with an entropy gain of 0.8R ln 4 at 32 K. The susceptibility shows a broad maximum at 1.8 K, while in the magnetization there is no trace of ordering up to 18 T at 1.5 and 4.2 K. We interpret the experimental results as governed by a quadruplet crystal field ground state, which undergoes a quadrupolar transition at 18 K. At lower temperatures a heavy-fermion ground state develops, with C(el)/T = 500 mJ/Ce at. K2 for T --> 0 and CHI-T/C(el) = 0.11 emu K/J for T < 5 K.
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Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0921-4526 ISBN Medium
Area Expedition Conference
Notes ISI:A1991FU47000062 Approved no
Call Number BT @ hernan @ Serial 120
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