Sereni, J. G. "New quantum-critical-point-related effects in Ce lattice systems." Physica B: Condensed Matter 354, no. 1-4 (2004): 331–337.
Abstract: Anomalous physical properties related to quantum critical points are investigated in Ce-systems whose magnetic phase boundaries, T-N,T-C(x,p), can be traced for at least one decade of temperature. A change from the usual negative curvature to a linear concentration, x, dependence of T-N,T-C(x) is observed at x* greater than or equal to x(cr/2) (x(cr) being the critical concentration). Within the x* < x < x(cr) region, the usual specific heat temperature dependence C-m/T proportional to Ln (1/T) develops above T-N,T-C, while a nearly constant value of C-m/T maximum is observed besides a scaling of C-m/T(T) with DeltaT = T – T-N,T-C. Coincidentally, a significant increase of the zero-point entropy S-0(x)(= RLn 2 – S-m(x, T)) occurs. Dimensionality and dynamics of the spin fluctuations can be analyzed computing the internal energy and entropy for T greater than or equal to T-N and AC-susceptibility results. Consequences for the free-energy evolution within this region and implications of the S-0(x) increase are discussed. (C) 2004 Elsevier B.V. All rights reserved.
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Sereni, J. G. "Scaling properties of Ce-lattice systems in their magnetic instability region." Physica B: Condensed Matter 320, no. 1-4 (2002): 376–379.
Abstract: In Ce-lattice systems the magnetic phase transition is progressively dominated by magnetic instabilities as the ordering temperature (T-N) is depressed by pressure (p) or alloying (z) the Ce-ligands. The magnetic excitations, related to those instabilities, become the largest contribution to the specific heat (C-el/T) and the entropy (DeltaS(m)) at T > T-N, as T-N(z,p) vanishes in different manners: by approaching a quantum critical point at T-N --> 0 (case-I), at finite temperature (case-II) or T-N remaining constant under z or p variation (case-III). We show that in each case C-el/T and DeltaS(m) are scaled by different dependencies on the two characteristic temperatures: T-N and T-0 (the last related to the 4f-band hybridization strength). Both energies depend on z or p in different forms. We observe that in case-I, C-el(z,p)/T and DeltaS(m) scale with DeltaT = T – T-N, with T-0 being only system dependent. For case-II we find a unique function for C-el/T(T > T-N), independent of T-N and T-0, and for the case-III DeltaS (T > T-N) is scaled by T/T-0(z, p), whereas T-N only depends on the system. (C) 2002 Elsevier Science B.V. All rights reserved.
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Sereni, J. G. "Magnetic Systems: Specific Heat." In Encyclopedia of Materials: Science and Technology, edited by K. H. J. Buschow, R. W. Cahn, M. C. Flemings, B. Ilschner, E. J. Kramer, S. Mahajan and P. Veyssière, 4986–4993. Vol. 5. Oxford: Elsevier, 2001.
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Sereni, J. G. "Thermodynamical analysis of the magnetic phase diagrams of Ce systems." Journal of the Physical Society of Japan 70, no. 7 (2001): 2139–2150.
Abstract: Three types of magnetic phase diagrams as a function of composition or pressure, f (z, p), are identified among Ce systems: I) with the ordering temperature T-ord --> 0 monotonously, followed by a narrow region where non-Fermi-liquid (NFL) behavior is observed; II) with T-ord vanishing at finite temperature, but followed by an extended NFL region, and III) where T-ord remains nearly constant. Among the analyzed systems intrinsic differences are found in the evolution of their respective properties, namely: in group-1 an increase of the density of excitations is observed below T-ord. In group-II the evanescense of T-ord(z, p) coincides with the extrapolation to zero of the magnetic free energy (DeltaG --> 0), and the existence of a reference function implying that T-K not equal f (z, p), whereas T-ord = f (z, p). Finally, group-III is also characterized by the evanescense of T-ord where DeltaG --> 0, but in this case T-ord not equal f (z, p) whereas T-K = f (z, p). The characteristics of each group are discussed and compared together with the different C-p(T)/T dependencies at T greater than or equal to T-ord and some related scalings, which allow to recognize a quasi-paramagnetic phase.
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Sereni, J. G. "Evanescence of magnetic transitions in Ce systems." Physica B – Condensed Matter 281-282 (2000): 337–339.
Abstract: Three types of magnetic phase diagrams can be identified in Ce systems: (I) with ordering temperature T-ord --> 0 continuously, followed by a narrow non-Fermi-liquid (NFL) region, (II) with T-ord vanishing at finite temperature, followed by an extended NFL region, and (III) where the degrees of freedom condensed into the ordered phase decreases, without a concomitant decrease of T-ord. Intrinsic differences are found in the way that the degrees of freedom condense at T-ord and from the rising of the specific heat tails above T-ord. (C) 2000 Elsevier Science B.V. All rights reserved.
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Sereni, J. G. "Acitividades de Investigación en Física en San Carlos de Bariloche." Revista Española de Física 13 (1999): 4.
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Sereni, J. G. "Las variadas facetas del magnetismo incipiente en compuestos de Cerio." Revista Española de Física 13 (1999): 25.
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Sereni, J. G. "Inestabilidad de valencia, divergencias a temperatura nula y superconductividad en compuestos de cerio." In Anales de la Academia de Ciencias Exactas, Físicas y Naturales, 119. Vol. 50. Buenos Aires, 1998.
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Sereni, J. G. "Comparative study of magnetic phase diagrams of Ce compounds." Journal of the Physical Society of Japan 67, no. 5 (1998): 1767–1775.
Abstract: Thermal properties of magnetically ordered Ce-lattice systems are compared in their crossover to the non-magnetic state, driven by alloying effects. The ordering temperature (T-ord=T-N or T-C) is found to go to zero continuously only in a few cases, while in others a discontinuity in its decrease is clearly observed. Coincidentally, the magnetic contribution to the specific heat (C-p), the entropy and the free energy variations with temperature mark an evident difference between those cases. Furthermore, the extension of the non-fermi-liquid (NFL) phase in terms of concentration variation correlates with differences observed in the respective ordered phase. A systematic transformation from a mean field like transition to a fluctuation dominated type is observed in C-p(T), as the system overcomes a characteristic crossover concentration. Such a concentration appears as a limit for the NFL behavior in the paramagnetic phase above T-ord. A possible origin of the mentioned differences are discussed in terms of some alternatives in the evolution of the magnetic moments and the strength of their interactions.
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Sereni, J. G. "CROSSOVER FROM MAGNETIC TO NON-MAGNETIC GROUND STATE IN CE SYSTEMS." In Current Trends in Strongly Correlated Electron Systems, edited by S.K. Malik. Vol. 1. Plenum Press, 1995.
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