Berger, S., R. Hauser, H. Michor, G. Hilscher, E. Bauer, J. G. Sereni, and P. Rogl. "Thermodynamic properties of Ce(RuxRh1-x)3B2." Physica B 259-261 (1999): 116–117.
Abstract: Investigations of the magnetic phase diagram of Ce(RuxRh1-x)(3)B-2 were complemented by detailed specific heat and susceptibility measurements revealing complex magnetic order without spontaneous magnetisation. This regime follows the ferromagnetic phase on Rh/Ru substitution for x greater than or similar to 0.06. (C) 1999 Elsevier Science B.V. All rights reserved.
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Encina, S., P. Pedrazzini, J. G. Sereni, and C. Geibel. "Low temperature thermopower and magnetoresistance of Sc-rich CeSc1-xTixGe." Physica B: Condensed Matter 536 (2018): 133–136.
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 Ï(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 Ï(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 Ï(T,H) is a proper tool to assess the H−T phase diagram of this system.
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Gomez Berisso, M., J. G. Sereni, A. Braghta, G. Schmerber, B. Chevalier, and J. P. Kappler. "Field suppression of the modulated phase of Ce2Pd2Sn." Physica B 404, no. 19 (2009): 2930–2933.
Abstract: Low temperature magnetic (M) and thermal (CP) properties of the intermetallic compound Ce2Pd2Sn have been investigated at zero and different magnetic fields. Two transitions were recognized at and , with latter nearly coinciding with the extrapolated Curie-Weiss temperature . The Curie factor evaluated from T>=TM, is [approximate]2μB. The positive value of θP, the triangular coordination of the magnetic (Ce) atoms and the weak effect of applied magnetic field, reveal that TM cannot be considered as a canonic antiferromagnetic transition like claimed in the literature. M(T) measurements under moderate magnetic fields () show TC(B) increasing while TM(B) is practically not affected. Both transition merge in a critical point at for , where the intermediate phase is suppressed. At , the cusp of a first order transition is observed in CP(T). According to the proposed ferromagnetic ground state, it is followed by a CP(T)[is proportional to]T3/2exp(-Eg/T) dependence, with a gap of anisotropy .
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Hartmann, S., M. Deppe, N. Oeschler, N. Caroca-Canales, J. G. Sereni, and C. Geibel. "Ferromagnetism in CePd1-xRhx single crystals." Journal of Optoelectronics and Advanced Materials 10, no. 7 (2008): 1607–1611.
Abstract: The orthorhombic CePd1-xRhx alloy exhibits a continuous evolution from a ferromagnetic ground state at x = 0 to
intermediate-valence behavior for x = 1. Here, we report on specific heat CP(T), resistivity Ï(T) and magnetization M(T)
measurements on single crystals in a Rh concentration range 0.2 < x < 0.65 exploring the ferromagnetic side of the
magnetic phase diagram. The transport and thermodynamic properties of the ferromagnetic phase have been investigated
in the temperature range from 300 K down to 0.35 K and analyzed in terms of a gap in the magnon spectrum and an
underlying Kondo contribution. Crystal electric field parameters are deduced from specific heat measurements well above
Tc- The competition between Kondo effect and ferromagnetism has been studied in dependence of the Rh concentration in
the system. Particularly, the enhanced Sommerfeld coefficient γ(x) indicates strong Kondo interactions when the Curie
temperature is reduced.
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Pedrazzini, P., D. Jaccard, M. Deppe, C. Geibel, and J. G. Sereni. "Multiprobe high-pressure experiments in CePd0.6Rh0.4 and CePd3." Physica B: Condensed Matter 404, no. 19 (2009): 2898–2903.
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.
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Rigal, L. B., D. C. Schmadel, H. D. Drew, B. Maiorov, E. Osquiguil, J. S. Preston, R. Hughes, and G. D. Gu. "Magneto-optical evidence for a gapped Fermi surface in underdoped YBa 2Cu3O6+x." Physical Review Letters 93, no. 13 (2004).
Abstract: An evidence presented that supports partial gapping of the Fermi surface by a measurement of the Hall frequency from high frequency magneto-optical measurements on underdoped YBa2Cu3O6+x (YBCO) was discussed. It was found that the Hall frequency was obtained independently of the unknown k-space dependence of the carrier scattering rates that complicated the dc Hall effect. It was observed that the frequency dependence of the Hall angle was Drude-like and indicated a quasielastic relaxation process for optimal and underdoped samples. The results show that there was an increase of the Hall frequency in the pseudogap state.
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