|   | 
Details
   web
Records
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.
Address
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:A1988M112900009 Approved no
Call Number BT @ hernan @ Serial 127
Permanent link to this record
 

 
Author (up) Braun, E.; Jackel, G.; Roden, B.; Sereni, J.G.; Wohlleben, D.
Title Comparative study of the specific heat of superconducting and non-superconducting YBa2Cu3O7-x Type Journal Article
Year 1988 Publication Zeitschrift für Physik B Condensed Matter Abbreviated Journal Z. Phys. B
Volume 72 Issue 2 Pages 169-173
Keywords
Abstract We have measured the specific heat, the electrical resistance and the magnetic susceptibility of YBa2Cu3O7−x in a superconducting (sc) and in a non-superconducting (nsc) version. The latter was obtained by inducing a small loss of oxygen. In the sc sample we find a jump of the specific heat with ΔC=3.6 J mole−1 K−1. Below the maximum nearT c the specific heat of the sc version drops too fast for an electronic effect alone: there is a cross-over from excess to deficiency already at 0.9T c . The specific heat of the nsc version shows a change of slope in the temperature range between 70 and 80 K, which indicates the existence of a second specific heat anomaly, which apparently exists independently of that due to the onset of superconductivity and explains at least partially the premature crossover.
Address
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:A1988P796500004 Approved no
Call Number BT @ hernan @ Serial 125
Permanent link to this record
 

 
Author (up) Kappler, J.P.; Haen, P.; Trovarelli, O.; Sereni, J.G.; Besnus, M.J.
Title Low temperature properties of Ce(Pd1-xAgx) Type Journal Article
Year 1996 Publication Zeitschrift für Physik B Condensed Matter Abbreviated Journal Z. Phys. B
Volume 101 Issue 1 Pages 29-34
Keywords
Abstract Low temperature magnetic, transport and thermal measurements on the Ce(Pd1-xAgx) system, with x ranging from 0 to 0.17, are presented. The magnetic structure of the ordered phase transforms from ferromagnetic to antiferromagnetic with only 2at.% Pd substitution, whereas reentrance of ferromagnetism is observed at 15at.% Ag content. We propose the break in the periodicity of the Coulomb potential (Pd is a hole-like atom, whereas Ag is an electron-like one) as the dominant effect for such a change in the magnetic behavior of this system.
Address
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:A1996VE20500005 Approved no
Call Number BT @ hernan @ Serial 94
Permanent link to this record
 

 
Author (up) KAPPLER, J.P.; SCHMERBER, G.; TROVARELLI, O.; SERENI, J.G.
Title COEXISTENCE OF HEAVY FERMION AND INTERMEDIATE VALENCE BEHAVIOR IN CE24CO11 Type Journal Article
Year 1992 Publication Zeitschrift für Physik B Condensed Matter Abbreviated Journal Z. Phys. B
Volume 86 Issue 2 Pages 253-256
Keywords
Abstract Low temperature specific heat, magnetic susceptibility and L(III)-XAS measurements on Ce24Co11 are reported. The electronic specific heat can be decomposed into two contributions: a low temperature one (arising at T < 5 K), with a maximum of 2.2 J/Kmole at 0.9 K, and another one becoming dominant at T > 5 K, characterized by a gamma(HT) = 1.8 J/K2mole coefficient. The chi.T product changes continuously with temperature, from 0.48 emu K/mole at 2 K to 7.85 emu K/mole at 200 K. The L(III)-mean valence is upsilon = 3.15. As the 24 Ce atoms are distributed in ten unequivalent crystalline sites, we interpret the experimental results as due to: one atom which behaves as a Heavy Fermion and the rest as Kondo and Intermediate Valent, with a distribution of characteristic energies governed by nine different environments. Qualitatively, the specific heat behaviour under applied field and the upsilon = 3.15 value are in agreement with this interpretation.
Address
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:A1992HD31000014 Approved no
Call Number BT @ hernan @ Serial 116
Permanent link to this record
 

 
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
Keywords
Abstract
Address
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
Permanent link to this record