toggle visibility Search & Display Options

Select All    Deselect All
 |   | 
Details
   print
  Records Links
Author Núñez Regueiro, M.; Esquinazi, P.; Izbizky, M.A.; Durán, C.; Castello, D.; Luzuriaga, J. doi  openurl
  Title Tunneling systems in high temperature superconductors Type Journal Article
  Year 1988 Publication Annales de Physique Abbreviated Journal Ann. Phys. Fr.  
  Volume 13 Issue 5 Pages 401-406  
  Keywords acoustic wave absorption; acoustic wave velocity; barium compounds; high temperature superconductors; lanthanum compounds; rare earth compounds; strontium compounds; superconductive tunnelling; thermal conductivity of solids; tunnelling systems; high temperature superconductors; thermal conductivity; sound attenuation; sound velocity; model; low temperature specific heat; La Sr Cu O  
  Abstract We have measured the thermal conductivity, sound attenuation and relative variation of sound velocity of compounds of the La-Sr-Cu-O and RBa2Cu3O7 families, where R is a rare-earth. We have found that all these properties can be quantitatively correlated within a tunneling system model similar to that used in amorphous materials. This interpretation would naturally explain the anomalous linear term of the low temperature specific heat observed in these materials.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (up)  
  Series Volume Series Issue Edition  
  ISSN 0003-4169 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:A1988Q715000009 Approved no  
  Call Number BT @ hernan @ Serial 264  
Permanent link to this record
 

 
Author Frank, V.L.P.; de la Cruz, M.E. url  doi
openurl 
  Title Low temperature specific heat of Dow Corning Silicon Oil No 704 between 2 and 18 K Type Journal Article
  Year 1984 Publication Cryogenics Abbreviated Journal  
  Volume 24 Issue 6 Pages 311-312  
  Keywords cryogenics; specific heat; silicon oil  
  Abstract The specific heat of Dow Corning Silicon Oil No 704 was measured between 2 and 18 K. Below 5 K it was found to follow a T3 law. Throughout the range it could be fitted with a 5th order polynomial in T.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (up)  
  Series Volume Series Issue Edition  
  ISSN 0011-2275 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 527  
Permanent link to this record
 

 
Author Pedrazzini, P.; Jaccard, D.; Deppe, M.; Geibel, C.; Sereni, J.G. url  doi
openurl 
  Title Multiprobe high-pressure experiments in CePd0.6Rh0.4 and CePd3 Type Journal Article
  Year 2009 Publication Physica B: Condensed Matter Abbreviated Journal Physica B  
  Volume 404 Issue 19 Pages 2898-2903  
  Keywords Ce compounds; Ferromagnetism; Quantum phase transition; High pressure; Resistivity; Seebeck coefficient; Specific heat  
  Abstract Results of recent multiprobe high-pressure experiments on ferromagnetic CePd0.6Rh0.4 and intermediate-valent CePd3 are presented. Simultaneous resistivity (ρ), thermopower (S), and ac heat capacity measurements show that the long-range ferromagnetic state of CePd0.6Rh0.4 vanishes in the proximity of a sharp valence-crossover pressure , i.e. before reaching a quantum critical point. However, a magnetic signal that is progressively suppressed is still detected at higher pressures. For CePd3, the results of simultaneous ρ(T,p) and S(T,p) measurements up to and down to the mK temperature range show a surprisingly weak pressure dependence.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (up)  
  Series Volume Series Issue Edition  
  ISSN 0921-4526 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ jsereni @ Serial 561  
Permanent link to this record
 

 
Author Sereni, J.G.; Schmerber, G.; Kappler, J.P. doi  openurl
  Title Thermodynamic Behavior of Ce Compounds Close to a T->0 Critical Point Type Journal Article
  Year 2013 Publication IEEE Transactions on Magnetics Abbreviated Journal IEEE Trans. Magn.  
  Volume 49 Issue 8 Pages 4647-4651  
  Keywords cerium compounds; critical points; entropy; palladium compounds; specific heat; CePd3Bx; CePd3Bex; cerium compounds; critical point; entropy; specific heat; thermodynamic behavior; Compounds; Entropy; Heating; Saturation magnetization; Temperature dependence; Temperature measurement; Thermodynamics; Cerium; magnetic properties; thermodynamics  
  Abstract There is a reduced group of Ce very heavy Fermions (VHF) which do not order magnetically down to at least T ≈ 500 mK because they are very close to a Tord = 0 critical point. These compounds are at the top of the limT→ 0 Cm/T specific heat values because they collect very high density of low energy excitations. From the analysis of Cm(T)/T and entropy Sm(T) dependencies performed on selected CePd3Mx ternaries (where M = B and Be) a quantitative evaluation of an upper limit for the density of excitations can be proposed. These observations exclude any evidence of Cm(T)/T divergency as T→ 0 in agreement with thermodynamic laws. A comparison with selected Yb-base VHF supports these features.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (up)  
  Series Volume Series Issue Edition  
  ISSN 0018-9464 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 664  
Permanent link to this record
 

 
Author Sereni, J.G. doi  openurl
  Title Entropy Bottlenecks at T->0 in Ce-Lattice and Related Compounds Type Journal Article
  Year 2015 Publication Journal of Low Temperature Physics Abbreviated Journal J. Low Temp. Phys.  
  Volume 179 Issue 1-2 Pages 126-137  
  Keywords Heavy fermions; Specific heat anomalies; Entropy  
  Abstract A number of specific heat Cm anomalies are reported in Ce- and Yb-lattice compounds around 1 K which cannot be associated to usual phase transitions despite of their robust magnetic moments. Instead of a Cm(T) jump, these anomalies show coincident morphology: (i) a significant tail in Cm/T , with similar power law decay above their maxima ( T>Tm ), (ii) whereas a Cm(T2) dependence is observed below Tm . (iii) The comparison of their respective entropy gain Sm(T) indicates that ≈0.7R ln2 is condensed within the T>Tm tail, in coincidence with an exemplary spin-ice compound. Such amount of entropy arises from a significant increase of the density of low energy excitations, reflected in a divergent Cm(T>Tm)/T dependence. (iv) Many of their lattice structures present conditions for magnetic frustration. The origin of these anomalies can be attributed to an interplay between the divergent density of magnetic excitations at T→0 and the limited amount of degrees of freedom: Sm = R ln2 for a doublet-ground state. Due to this “entropy bottleneck,” the paramagnetic minimum of energy blurs out and the system slides into an alternative minimum through a continuous transition. A relevant observation in these very heavy fermion systems is the possible existence of an upper limit for Cm/TLimT→0 ≈7 J/mol K 2 observed in four Yb- and Pr-based compounds.  
  Address  
  Corporate Author Thesis  
  Publisher Springer US Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (up)  
  Series Volume Series Issue Edition  
  ISSN 0022-2291 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 709  
Permanent link to this record
 

 
Author Sereni, J.G. url  doi
openurl 
  Title Thermomagnetic properties of very heavy fermions suitable for adiabatic demagnetisation refrigeration at low temperature Type Journal Article
  Year 2020 Publication Philosophical Magazine Abbreviated Journal Philos. Mag.  
  Volume 100 Issue 10 Pages 1211  
  Keywords Magnetic refrigeration; heavy fermions; entropy; frustration; specific heat  
  Abstract With the aim to improve the performance of classical paramagnetic salts for adiabatic refrigeration processes at the sub-Kelvin range, relevant thermodynamic parameters of some new Yb-based intermetallic compounds are analysed and compared. Two main applications are considered: (i) those requiring temperature fixed-points to be reached applying magnetic fields of moderate intensity for satellite applications, and (ii) those which can be used for controlled thermal drifts in laboratory applications. Different thermomagnetic trajectories of the entropy are identified depending on respective specific heat behaviours and the constraints imposed by the Nernst postulate at the sub-Kelvin range. Some simple relationships are proposed to compare the diverse magnetocaloric characteristics of different systems. This procedure allows to include the classical Cerium-Magnesium-Nitride (CMN) salt in that comparison.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (up)  
  Series Volume Series Issue Edition  
  ISSN 1478-6435 ISBN Medium  
  Area Expedition Conference  
  Notes Special Issue in Honour of M. Brian Maple Approved no  
  Call Number BT @ pedrazp @ Serial 862  
Permanent link to this record
 

 
Author Franco, D.G.; Geibel, C. url  doi
openurl 
  Title Synthesis and study of the chiral magnetic system EuIr2P2 Type Journal Article
  Year 2021 Publication Physical Review B Abbreviated Journal Phys. Rev. B  
  Volume 104 Issue Pages 054416  
  Keywords Frustrated magnetism; Antiferromagnets; Specific heat; X-ray diffraction  
  Abstract Chiral materials, where no improper symmetry operations such as inversion are resent, are systems prone to the appearance of a skyrmion lattice. Recently it has been shown theoretically that not only ferromagnets (FMs) but also antiferromagnets (AFMs) can host such kind of phases. In this work we study a new candidate for AFM skyrmions, EuIr2P2, by means of magnetization and specific heat measurements on poly and single crystals. X-ray diffraction confirms a trigonal chiral crystal structure, where europium ions form helices along the c direction. In spite of predominantly FM interactions, Eu2+ ions order antiferromagnetically at

TN1=5 K in what seems to be an incommensurate amplitude-modulated magnetic state where the moments are oriented mainly along the c direction. A second magnetic transition takes place at TN2=2.9 K, involving the ordering of an in-plane component of the Eu moment likely resulting in an equal-moment structure. Specific heat data show a tail above TN1. Accordingly the magnetic entropy at

TN1 is strongly reduced in comparison to the expected Rln8 value. This evidences a significant amount of frustration. A simple analysis based on a Heisenberg model indicates that the observed properties imply the presence of several relevant interactions, with competing FM and AFM ones resulting in frustration. Thus

EuIr2P2 is a new interesting magnetic system, where chirality and frustration might result in unconventional magnetic textures.
 
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title (up)  
  Series Volume Series Issue Edition  
  ISSN 2469-9950 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 877  
Permanent link to this record
Select All    Deselect All
 |   | 
Details
   print

Save Citations:
Export Records: