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Author (up) Berisso, M.G.; Pedrazzini, P.; Deppe, M.; Trovarelli, O.; Geibel, C.; Sereni, J.G. openurl 
  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  
  Keywords  
  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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  Series Volume Series Issue Edition  
  ISSN 0921-4526 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000177607700103 Approved no  
  Call Number BT @ hernan @ Serial 294  
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Author (up) Berisso, M.G.; Pedrazzini, P.; Sereni, J.G.; Trovarelli, O.; Geibel, C.; Steglich, F. openurl 
  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  
  Keywords  
  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  
  Area Expedition Conference  
  Notes ISI:000180850100009 Approved no  
  Call Number BT @ hernan @ Serial 69  
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Author (up) Berisso, M.G.; Trovarelli, O.; Pedrazzini, P.; Zwicknagl, G.; Geibel, C.; Steglich, F.; Sereni, J.G. url  doi
openurl 
  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  
  Keywords  
  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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  Series Volume Series Issue Edition  
  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 (up) Correa, V.F.; Betancourth, D.; Sereni, J.G.; Caroca-Canales, N.; Geibel, C. url  doi
openurl 
  Title Remarkable magnetostructural coupling around the magnetic transition in CeCo0.85Fe0.15Si Type Journal Article
  Year 2016 Publication Journal of Physics: Condensed Matter Abbreviated Journal J. Phys.: Condens. Matter  
  Volume 28 Issue 34 Pages 346003  
  Keywords magnetostriction, cerium compounds, magnetism  
  Abstract We report a detailed study of the magnetic properties of CeCo0.85Fe0.15Si under high magnetic

fields (up to 16 Tesla) measuring different physical properties such as specific heat, magnetization,

electrical resistivity, thermal expansion and magnetostriction. CeCo0.85Fe0.15Si becomes

antiferromagnetic at TN 6.7 K. However, a broad tail (onset at TX 13 K) in the specific heat

precedes that second order transition. This tail is also observed in the temperature derivative of

the resistivity. However, it is particularly noticeable in the thermal expansion coefficient where it

takes the form of a large bump centered at TX. A high magnetic field practically washes out that tail

in the resistivity. But surprisingly, the bump in the thermal expansion coefficient becomes a well

pronounced peak fully split from the magnetic transition at TN. Concurrently, the magnetoresistance

also switches from negative to positive above TN. The magnetostriction is considerable and

irreversible at low temperature ( (16T)4×10− L

L

4 at 2 K) when the magnetic interactions

dominate. A broad jump in the field dependence of the magnetostriction observed at low T may be

the signature of a weak ongoing metamagnetic transition. Taking altogether the results indicate the

importance of the lattice effects on the development of the magnetic order in these alloys.
 
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  Notes Approved no  
  Call Number BT @ victor.correa @ Serial 732  
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Author (up) Correa, V.F.; Curci, I.; Sereni, J.G.; Caroca Canales, N.; Geibel, C. url  doi
openurl 
  Title Magnetic-field-tuned valence susceptibility in CeCo1−xFexSi revealed by magnetostriction Type Conference Article
  Year 2022 Publication Journal of Physics: Conference Series Abbreviated Journal J. Phys.: Conf. Ser.  
  Volume 2164 Issue Pages 012042  
  Keywords  
  Abstract We report magnetoelastic studies in the CeCo1−xFexSi alloys. Iron doping has a profound effect on the low temperature linear magnetostriction. At T = 2 K, the strength of the magnetostriction peaks at x = 0.23 where it reaches a value as large as $\[\frac{{\Delta L}}{L} = 3 \times {10^{ – 3}}\]$ in an applied magnetic field B = 16 T. This Fe concentration corresponds to the critical one xc above which long-range antiferromagnetic order is no longer observed. The progressive increment of the hibridization between the Ce 4f orbital and the conduction band, as the magnetic order vanishes, gives rise to a sizeable valence susceptibility that can be finely tuned by the magnetic field explaining the large magnetostrictive effect around xc. At higher x, the magnetostriction decreases, in agreement with a weaker valence susceptibility resulting from a stronger hibridization.  
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  Notes Approved no  
  Call Number BT @ victor.correa @ Serial 880  
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Author (up) Custers, J.; Cichorek, T.; Gegenwart, P.; Caroca-Canales, N.; Stockert, O.; Geibel, C.; Steglich, F.; Pedrazzini, P.; Sereni, J.G. openurl 
  Title Non-Fermi liquid effects close to a QCP in CeIn3-xSnx Type Journal Article
  Year 2003 Publication ACTA PHYSICA POLONICA B Abbreviated Journal  
  Volume 34 Issue 2 Pages 379-382  
  Keywords  
  Abstract Resistivity and specific heat measurements at low temperatures on CeIn3-xSnx samples with concentrations x = 0.6, 0.65 and 0.7 demonstrate that with increasing Sn-alloying, the antiferromagnetic ordering temperature decreases continuously down to T = 0 K and disappears at a quantum critical point. We observe non-Fermi liquid (NFL) behavior in the resistivity and the specific heat, however the temperature dependencies are different from the predictions for a spin density wave (SDW) scenario. The resistivity at the critical point shows e.g., a linear temperature dependence, as expected for two dimensional fluctuations, which however can be excluded in the cubic structure of CeIn3-xSnx.  
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  Series Volume Series Issue Edition  
  ISSN 0587-4254 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000181544200015 Approved no  
  Call Number BT @ hernan @ Serial 68  
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Author (up) Deppe, M.; Caroca-Canales, N.; Sereni, J.G.; Geibel, C. url  doi
openurl 
  Title Evidence for a metamagnetic transition in the heavy Fermion system CeTiGe Type Conference Article
  Year 2010 Publication Journal of Physics: Conference Series Abbreviated Journal J. Phys.: Conf. Ser.  
  Volume 200 Issue Pages 012026  
  Keywords Applied magnetic fields; Canonical systems; Continuous suppression; Critical behavior; Critical fields; DC magnetization; First order; Heavy fermion systems; Higher temperatures; Low temperatures; Metamagnetic; Metamagnetic transitions; Polycrystalline; Cerium; Cerium compounds; Electric resistance; Magnetic field effects; Magnetoresistance; Magnetism  
  Abstract A recent study of CeTiGe identified this compound as a paramagnetic heavy Fermion system where the full J = 5/2 multiplet is involved in the formation of the ground state. Here we present a preliminary investigation of the dc-magnetization Mdc(H) and of the magnetoresistance ρ(H) of polycrystalline CeTiGe samples in applied magnetic fields up to μ0H = 14 T. The results reveal a pronounced metamagnetic transition at a critical field μ0Hc ≈ 13.5 T at low temperatures, with a step like increase in Mdc(H) of at least 0.6 μB/Ce. The metamagnetic transition leads to a strong decrease in ρ(H). A clear hysteresis in Mdc(H) and ρ(H) indicate that in CeTiGe these metamagnetic features correspond to a true thermodynamic, first order type transition in contrast to the critical behavior observed in the canonical system CeRu2Si2. Measurements at higher temperatures showed a continuous suppression of the metamagnetic transition with increasing T, which vanishes at T ∼ 30 K. © 2010 IOP Publishing Ltd.  
  Address  
  Corporate Author Thesis  
  Publisher Place of Publication Karlsruhe Editor  
  Language Summary Language Original Title  
  Series Editor Series Title International Conference on Magnetism, ICM 2009 Abbreviated Series Title  
  Series Volume 200 Series Issue SECTION 1 Edition  
  ISSN 17426588 (ISSN) ISBN Medium  
  Area Expedition Conference  
  Notes Conference code: 81773; Export Date: 10 December 2010; Source: Scopus; Art. No.: 012026; doi: 10.1088/1742-6596/200/1/012026; Language of Original Document: English; Correspondence Address: Deppe, M.; Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany; email: Hicha.Deppe@cpfs.mpg.de; References: Gegenwart, P., Si, Q., Steglich, F., (2008) Nature Phys., 4 (3), p. 186; Sachdev, S., (2008) Nature Phys., 4 (3), p. 173; Blundell, S., (2001) Oxford Master Series in Condensed Matter Physics, , (Oxford University Press); Monthoux, P., Lonzarich, G.G., (2001) Phys. Rev., 63 (5), p. 054529; Morozkin, A.V., Seropegin Yu, D., Leonov, A.V., Sviridov, I.A., Tskhadadze, I.A., Nikitin, S.A., (1998) J. Alloys Comput., 267, pp. 14-15R; Welter, R., Vernière, A., Venturini, G., Malaman, B., (1999) J. Alloys. Compounds, 283 (1-2), p. 54; Deppe, M., Caroca-Canales, N., Hartmann, S., Oeschler, N., Geibel, C., (2009) J. Phys.: Condens. Matter, 21 (20), p. 206001; Hewson, A.C., (1993) The Kondo Problem to Heavy Fermions (Cambridge Studies in Magnetism), 2. , ed D Edwards and D Melville (Cambridge: Cambridge University press); Haen, P., Flouquet, J., Lapierre, F., Lejay, P., Remenyi, G., (1987) J. Low Temp. Phys., 67 (5-6), p. 391; Sakakibara, T., Tayama, T., Matamura, K., Maezawa, K., Onuki, Y., Amitsuka, H., (1995) Phys. Rev., 51 (17), p. 12030; Andreev, A.V., Vejpravov, J., ProkleÅ¡ka, J., Sechovsky, V., (2008) Physica, 403 (5-9), p. 744 Approved no  
  Call Number BT @ berisso @ Serial 599  
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Author (up) Encina, S.; Pedrazzini, P.; Sereni, J.G.; Geibel, C. url  doi
openurl 
  Title Low temperature thermopower and magnetoresistance of Sc-rich CeSc1-xTixGe Type Journal Article
  Year 2018 Publication Physica B: Condensed Matter Abbreviated Journal Physica B  
  Volume 536 Issue Pages 133-136  
  Keywords CeScGe; CeTiGe; Antiferromagnetism; Transport properties; Low temperatures; Magnetic field  
  Abstract In CeSc1-xTixGe, Ti-alloying reduces the record-high antiferromagnetic (AFM) ordering temperature found in CeScGe at TN=46K and induces ferromagnetism for x≥0.5. In this work we focus on the AFM side, i.e. Sc-rich samples, and study their thermopower S(T) and magnetoresistance ρ(H,T). The measured S(T) is small in comparison with the thermopower of other Ce-systems and shows some features that are compatible with a weak hybridization between the 4f and band states. This is a further hint pointing to the local character of magnetism in this alloy. Magnetic fields up to 16T have a minor effect on the electrical resistivity of stoichiometric CeScGe. On the other hand, for x=0.65, we find that fields above 4T suppress the hump in ρ(T). Furthermore, the 4.2K magnetoresistance displays a strong decrease in the same field range, also in coincidence with magnetization results from the literature. Our results indicate that ρ(T,H) is a proper tool to assess the H−T phase diagram of this system.  
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  ISSN 0921-4526 ISBN Medium  
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  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 765  
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Author (up) 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.
 
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  ISSN 2469-9950 ISBN Medium  
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  Notes Approved no  
  Call Number BT @ pedrazp @ Serial 877  
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Author (up) Gomez-Berisso, M.; Pedrazzini, P.; Sereni, J.G.; Trovarelli, O.; Geibel, C.; Steglich, F. openurl 
  Title Low-temperature properties of the Ce(Pd1-rRhr)(2)Si-2 system Type Journal Article
  Year 1999 Publication PHYSICA B Abbreviated Journal  
  Volume 258-261 Issue Pages 68-69  
  Keywords  
  Abstract The ground state of the Ce(Pd1-rRhr)(2)Si-2 system is studied by means of magnetic susceptibility and low-temperature specific heat measurements (Cp) throughout the concentration range. The antiferromagnetic order of both stoichiometric extremes (T-N = 10.3 and 36 K for r = 0 and 1, respectively) drops abruptly below 0.4 K with mon than 30% of Pd substitution by Rh and 20% of Rh substitution by Pd on the respective sides. No magnetic order is observed between those concentrations, where the low-temperature behaviour is characterized by a C-P(T --> 0)/T divergency that continuously decreases (like the asociated entropy gain) as the Ph concentration increases. (C) 1999 Elsevier Science B.V. All rights reserved.  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0921-4526 ISBN Medium  
  Area Expedition Conference  
  Notes ISI:000079315700030 Approved no  
  Call Number BT @ hernan @ Serial 80  
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