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Author Correa, V.F.; Betancourth, D.; Sereni, J.G.; Caroca-Canales, N.; Geibel, C.
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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Call Number BT @ victor.correa @ Serial 732
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Author Deppe, M.; Caroca-Canales, N.; Sereni, J.G.; Geibel, C.
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.
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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., Prokleška, J., Sechovsky, V., (2008) Physica, 403 (5-9), p. 744 Approved no
Call Number BT @ berisso @ Serial 599
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Author Sereni, J.G.; Schmerber, G.; Kappler, J.P.
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.
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ISSN 0018-9464 ISBN Medium
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Call Number BT @ pedrazp @ Serial 664
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