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Aragón Sánchez, J.; Cortés Maldonado, R.; Cejas Bolecek, N.R.; Rumi, G.; Pedrazzini, P.; Dolz, M.I.; Nieva, G.; Beek, C.J. van der; Konczykowski, M.; Dewhurst, C.D.; Cubitt, R.; Kolton, A.B.; Pautrat, A.; Fasano, Y. | ||||
| Title | Unveiling the vortex glass phase in the surface and volume of a type-II superconductor | Type | Journal Article | ||
| Year | 2019 | Publication | Communications Physics | Abbreviated Journal | Commun. Phys. |
| Volume | 2 | Issue | 1 | Pages | 143 |
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| Abstract | Order-disorder transitions between glassy phases are common in nature and yet a comprehensive survey on the entailed structural changes is challenging since the constituents are in the micro-scale. Vortex matter in type-II superconductors is a model system where some of these experimental challenges can be tackled. Samples with point disorder present a glassy transition on increasing the density of vortices. A glassy yet quasi-crystalline phase, the Bragg glass, nucleates at low densities. The vortex glass stable at high densities is expected to be disordered, however its detailed structural properties remained experimentally elusive. Here we show that the vortex glass has large crystallites with in-plane positional displacements growing algebraically and short-range orientational order. Furthermore, the vortex glass has a finite and almost constant correlation length along the direction of vortices, in sharp contrast with strong entanglement. These results are important for the understanding of disorder-driven phase transitions in glassy condensed matter. | ||||
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| ISSN | 2399-3650 | ISBN | Medium | ||
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| Notes | Approved | no | |||
| Call Number | BT @ pedrazp @ Aragón Sánchez2019 | Serial | 843 | ||
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Bauer, E.; Galatanu, A.; Rogl, P.; Berisso, M.G.; Pedrazzini, P.; Sereni, J.G. | ||||
| Title | Loss of magnetism in CePd2-xNixAl3 | Type | Journal Article | ||
| Year | 2002 | Publication | PHYSICA B-CONDENSED MATTER | Abbreviated Journal | |
| Volume | 312 | Issue | Pages | 464-465 | |
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| Abstract | Hexagonal CePd2-xNixAl3 exhibits a crossover from a Kondo lattice showing magnetic order at T(N)similar or equal to2.8 K for xless than or equal to0.2 to intermediate valence (IV) for x-->2. Though T-N(x) is weakly affected upon Pd/Ni substitution before vanishing at finite temperature, the Kondo temperature T-K progressively increases. Above xsimilar or equal to0.3 the phase boundary no longer exists and strong spin fluctuations cause pronounced deviations from a Fermi-liquid ground state before the IV regime is established for xgreater than or equal to1. (C) 2002 Elsevier Science B.V. All rights reserved. | ||||
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| ISSN | 0921-4526 | ISBN | Medium | ||
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| Notes | ISI:000175871000171 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 296 | ||
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Bauer, E.; Hauser, R.; Galatanu, A.; Michor, H.; Hilscher, G.; Sereni, J.; Berisso, M.G.; Pedrazzini, P.; Galli, M.; Marabelli, F.; Bonville, P. | ||||
| Title | Non-Fermi-liquid behavior of YbCu5-xAlx | Type | Journal Article | ||
| Year | 1999 | Publication | Physical Review B | Abbreviated Journal | Phys. Rev. B |
| Volume | 60 | Issue | 2 | Pages | 1238-1246 |
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| Abstract | A valency change in YbCu5-xAlx from nu approximate to 2.2(x=0) to nu=3(x=2) causes a magnetic instability near a critical concentration x(cr)approximate to 1.5 Alloys in the vicinity of x(cr) exhibit typical non-Fermi-liquid properties like a negative logarithmic contribution to the specific heat or substantial deviations of the electrical resistivity from a T-2 behavior. Both pressure and alloying in this series bring about a strong reduction of the Kondo temperature T-K; the crystal-held interaction and the interatomic exchange gain therefore importance and magnetic order becomes possible beyond x(cr). | ||||
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| ISSN | 0163-1829 | ISBN | Medium | ||
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| Notes | ISI:000081563800070 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 301 | ||
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Berger, S.; Galatanu, A.; Hilscher, G.; Michor, H.; Paul, C.; Bauer, E.; Rogl, P.; Gomez-Berisso, M.; Pedrazzini, P.; Sereni, J.G.; Kappler, J.P.; Rogalev, A.; Matar, S.; Weill, F.; Chevalier, B.; Etourneau, J. | ||||
| Title | Experimental study of physical properties in the complex magnetic phase diagram of Ce(Rh1-xRux)(3)B-2 | Type | Journal Article | ||
| Year | 2001 | Publication | Physical Review B | Abbreviated Journal | Phys. Rev. B |
| Volume | 64 | Issue | 13 | Pages | 134404 |
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| Abstract | We report on a series of structural, magnetic, and thermodynamic measurements, a study of transport properties and x-ray absorption edge spectroscopy on Ce(Rh1-xRux)(3)B-2. These investigations evidence that in addition to the already established ferromagnetic range for x less than or equal to0.06, a complex antiferromagnetic structure exists for concentrations 0.1 less than or equal tox less than or equal to0.35. The behavior in the latter regime is dominated by an extraordinary strong intersite coupling; however, the magnetic moments involved appear to be very small. At the phase boundary to the paramagnetic regime (x approximate to0.4), significant deviations from a Fermi-liquid behavior occur. | ||||
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| ISSN | 0163-1829 | ISBN | Medium | ||
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| Notes | ISI:000171426700059 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 74 | ||
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| Author |
Berisso, M.G.; Pedrazzini, P.; Deppe, M.; Trovarelli, O.; Geibel, C.; Sereni, J.G. | ||||
| Title | Composition dependence of the magnetic properties of Ge-doped CeCu2Si2 | Type | Journal Article | ||
| Year | 2002 | Publication | PHYSICA B-CONDENSED MATTER | Abbreviated Journal | |
| Volume | 320 | Issue | 1-4 | Pages | 380-383 |
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| Abstract | Due to the proximity of CeCu2Si2 to a quantum critical point, the ground state of this compound is extremely sensitive to sample preparation conditions. Small excess of one component can lead to magnetic or superconducting behaviors. We found that in the alloy CeCu2(Si1-xGex)(2) a small excess of Ge enhances the homogeneity range allowing a precise investigation of stoichiometric effects on the physical properties. In this system, Ge doping produces an increment of the antiferromagnetic transition temperature T-N, while the superconducting one decreases. Particularly, it was found that at x = 0.1 both phases coexist at low temperature. In order to investigate the stability of these phases against changes of the Ce-ligands composition, we prepared a series of CeCu2+y(Si0.9Ge0.1)2-x, samples (0less than or equal toyless than or equal to0.10) and investigated their specific heat and electrical resistivity. We observed that the substitution of Si/Ge by Cu increases the characteristic temperature and weakens the magnetic contribution without modifying TN. A further transition, of the first order character, is observed at lower temperature. (C) 2002 Elsevier Science B.V. All rights reserved. | ||||
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| ISSN | 0921-4526 | ISBN | Medium | ||
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| Notes | ISI:000177607700103 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 294 | ||
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| Author |
Berisso, M.G.; Pedrazzini, P.; Sereni, J.G.; Trovarelli, O.; Geibel, C.; Steglich, F. | ||||
| Title | Study of Ce(Rh1-xPdx)(2)Si-2: pronounced differences between the CeRh2Si2 and CePd2Si2 ground states | Type | Journal Article | ||
| Year | 2002 | Publication | EUROPEAN PHYSICAL JOURNAL B | Abbreviated Journal | |
| Volume | 30 | Issue | 3 | Pages | 343-349 |
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| Abstract | We present electrical resistivity and specific heat measurements of alloys on the Rh rich side of the phase diagram of the Ce(Rh1-xPdx)(2)Si-2 system. We compare these results with those obtained at intermediate and low Rh concentrations. The analysis of the concentration and temperature dependence of the entropy and of the scaling behaviour of C-et(T) and rho(T) clearly confirm a separation of the magnetic phase diagram into two regions: the region x less than or equal to 0.3, showing a concentration independent characteristic temperature for the 4f-electrons with T-0 approximate to 45 K, while for x > 0.3, T-0 decreases to T-0(x = 1) approximate to 15 K. At low Pd-content, T-N decreases very rapidly from T-N = 36 K in pure CeRh2Si2 to T-N = 18 K at x = 0.1. With higher Pd concentration T-N stabilizes at T-N approximate to 15 K whereas the magnitude of the anomalies in C-et(T) and in the susceptibility around T-N are further reduced and disappear at x approximate to 0.3. This differs from the behavior found on the Pd-rich side, where T-N decreases continuously to zero with increasing Rh content. The pronounced differences observed between both phase boundaries and the drastic effect of doping on the Rh rich side suggest an itinerant character in CeRh2 Si-2, in contrast with the localized character of CePd2Si2. Further evidence for the itinerant character of CeRh2Si2 is given by the rho(T) dependence observed for x less than or equal to 0.3, which scales with rho(T) of the prototype itinerant compound YCo2. | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1434-6028 | ISBN | Medium | ||
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| Notes | ISI:000180850100009 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 69 | ||
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| Author |
Berisso, M.G.; Trovarelli, O.; Pedrazzini, P.; Zwicknagl, G.; Geibel, C.; Steglich, F.; Sereni, J.G. | ||||
| Title | Nonmonotonous evolution of the Kondo temperature in the phase diagram of Ce(Pd1-xCux)(2)Si-2 | Type | Journal Article | ||
| Year | 1998 | Publication | Physical Review B – Condensed Matter and Materials Physics | Abbreviated Journal | Phys. Rev. B |
| Volume | 58 | Issue | 1 | Pages | 314-321 |
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| Abstract | The evolution of the behavior of the Ce 4f electron with the Cu content in the alloy Ce(Pd1-xCux)(2)Si-2 was investigated by determining its structural, magnetic, transport, and thermal properties. Results obtained on 15 samples with compositions distributed along the whole concentration range allow us to draw a magnetic phase diagram showing three distinct regions. The first region at low Cu concentrations corresponds to the antiferromagnetic-ordered regime. The fast suppression of this magnetic order between x = 0.2 and x = 0.25 suggests the presence of a critical point which separates this region from the second one at larger.x values where no magnetic order is observed. The main characteristic of this second region, which extends up to x = 0.7, is a pronounced increase of the Kondo temperature T-K, from T-K approximate to 15 K at x = 0.25 to T-K approximate to 50 K at x = 0.7. This is in contrast with the fast decrease of T-K in the region with x > 0.7. In this region a small anomaly with a ferromagnetic character is observed in the specific hear arround 4 K. The change in the evolution of T-K with x coincides with a change in the composition dependence of the c lattice parameter of the tetragonal structure, pointing to a structure-related origin of this unusual T-K(x) behavior. This nonmonotonous T-K(x) dependence is reproduced using local-density-approximation band-structure calculations, which show a maximum of the hybridization strength between conduction electrons and Ce 4f stares for intermediate Cu concentrations. Such a T-K(x) dependence which contradicts the monotonous dependence observed in all other Ce-based alloy systems is the hallmark of the Ce(Pd1-xCux)(2)Si-2 alloy, which cannot be described as a Fermi-Liquid system in the nonmagnetic region. [S0163-1829(98)02118-3]. | ||||
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| ISSN | 0163-1829 | ISBN | Medium | ||
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| Notes | ISI:000074643200061 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 302 | ||
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| Author |
Betancourth, D.; Facio, J.I.; Pedrazzini, P.; Jesus, C.B.R.; Pagliuso, P.G.; Vildosola, V.; Cornaglia, P.S.; García, D. J.; Correa, V. F. | ||||
| Title | Low Temperature magnetic properties of GdCoIn5 | Type | Journal Article | ||
| Year | 2015 | Publication | Journal of Magnetism and Magnetic Materials | Abbreviated Journal | J. Magn. Magn. Mater. |
| Volume | 374 | Issue | Pages | 744-747 | |
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| Abstract | A comprehensive experimental and theoretical study of the low temperature properties of GdCoIn5 was performed. Specific heat, thermal expansion, magnetization and electrical resistivity were measured in good quality single crystals down to 4He temperatures. All the experiments show a second-order-like phase transition at 30 K probably associated with the onset of antiferromagnetic order. The magnetic susceptibility shows a pronounced anisotropy below T N with an easy magnetic axis perpendicular to the crystallographic ĉ-axis. Total energy GGA+U calculations indicate a ground state with magnetic moments localized at the Gd ions and allowed a determination of the Gd-Gd magnetic interactions. Band structure calculations of the electron and phonon contributions to the specific heat together with Quantum Monte Carlo calculations of the magnetic contributions show a very good agreement with the experimental data. Comparison between experiment and calculations suggests a significant anharmonic contribution to the specific heat at high temperature (View the MathML sourceT≳100K). | ||||
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| Notes | Approved | no | |||
| Call Number | BT @ victor.correa @ | Serial | 701 | ||
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| Author |
Bridoux, G.; Pedrazzini, P.; de la Cruz, F.; Nieva, G. | ||||
| Title | Angular field dependence of the Nernst effect in Bi2Sr2CaCu2O8+delta | Type | Journal Article | ||
| Year | 2007 | Publication | PHYSICA C-SUPERCONDUCTIVITY AND ITS APPLICATIONS | Abbreviated Journal | |
| Volume | 460 | Issue | Pages | 841-842 | |
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| Abstract | The anomalous Nernst effect in hole-doped cuprates has been interpreted in terms of the existence of a superconducting order parameter well above the transition temperature, T-c(H). In order to improve the understanding of this problem, we have measured the angular field dependence of the Nernst signal in Bi2Sr2CaCu2O8+delta single crystals. The experiment was done tilting the magnetic field with respect to the direction of the temperature gradient, above and below T,(H), with applied fields up to 16 T. We have found that all the curves are scaled on one curve against the reduced field Hcos theta at a fixed temperature. (c) 2007 Elsevier B.V. All rights reserved. | ||||
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| ISSN | 0921-4534 | ISBN | Medium | ||
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| Notes | ISI:000249870600060 | Approved | no | ||
| Call Number | BT @ hernan @ | Serial | 198 | ||
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| Author |
Carreras Oropesa, W.G.; Encina, S.; Pedrazzini, P.; Correa, V.F.; Sereni, J.G.; Vildosola, V.; García D.J.; Cornaglia, P.S. | ||||
| Title | Minimal model for the magnetic phase diagram of CeTi1-xScxGe, GdFe1-xCoxSi, and related materials | Type | Journal Article | ||
| Year | 2020 | Publication | Journal of Magnetism and Magnetic Materials | Abbreviated Journal | |
| Volume | 503 | Issue | Pages | 166614 | |
| Keywords | Magnetism; RTX | ||||
| Abstract | We present a theoretical analysis of the magnetic phase diagram of CeTi1-xScxGe and GdFe1-xCoxSi as a function of the temperature and the Sc and Co concentration x, respectively. CeScGe and GdCoSi, as many other RTX (R=rare earth, T=transition metal, X=p-block element) compounds, present a tetragonal crystal structure where bilayers of R are separated by layers of T and X. While GdFeSi and CeTi0.75Sc0.25Ge are ferromagnetic, CeScGe and GdCoSi order antiferromagnetically with the R 4f magnetic moments on the same bilayer aligned ferromagnetically and magnetic moments in nearest neighbouring bilayers aligned antiferromagnetically. The antiferromagnetic transition temperature TN decreases with decreasing concentration x in both compounds and for low enough values of x the compounds show a ferromagnetic behavior. Based on these observations we construct a simplified model Hamiltonian that we solve numerically for the specific heat and the magnetization. We find a good qualitative agreement between the model and the experimental data. Our results show that the main magnetic effect of the Sc→Ti and Co→Fe substitution in these compounds is consistent with a change in the sign of the exchange coupling between magnetic moments in neighbouring bilayers. We expect a similar phenomenology for other magnetic RTX compounds with the same type of crystal structure. |
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| Notes | Approved | no | |||
| Call Number | BT @ victor.correa @ | Serial | 856 | ||
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