Physical properties of CeIrSi with trillium-lattice frustrated magnetism

Magnetic (χ), transport (ρ), and heat capacity (Cm) properties of CeIrSi are investigated to elucidate the effect of geometric frustration in this compound with trillium type structure because, notwithstanding its robust effective moment, μeff≈2.46μB, this Ce-lattice compound does not undergo a magnetic transition. In spite of that it shows broad Cm(T)/T and χ(T) maxima centered at Tmax≈1.5 K, while a ρ-T2 thermal dependence, characteristic of electronic spin coherent fluctuations, is observed below Tcoh≈2.5 K. Magnetic field does not affect significantly the position of the mentioned maxima up to ≈1 T, though χ(T) shows an incipient structure that completely vanishes at μ0H≈1 T. Concerning the ρ-T2 dependence, it is practically not affected by magnetic field up to μ0H=9 T, with the residual resistivity ρ0(H) slightly decreasing and Tcoh(H) increasing. These results are compared with the physical properties observed in other frustrated intermetallic compounds.Fil: Kneidinger, F.. Institute of Solid State Physics; AustriaFil: Zeiringer, I.. Universidad de Viena; AustriaFil: Siderenko, A.. Institute of Solid State Physics; AustriaFil: Bauer, E.. Institute of Solid State Physics; AustriaFil: Michor, Herwig. Institute of Solid State Physics; AustriaFil: Rogl, P.. Universidad de Viena; AustriaFil: Sereni, Julian Gustavo Renzo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Centro Atómico Bariloche; Argentin

Crystal structure and Ce valence variation in the solid solution CeRh3-xPdxB0.5

Crystal structure and physical properties have been studied in the solid solution CeRh3-xPdxB0.5 (x = 0, 0.5, 1.2, 1.5, 1.7, 2.5, 3) in as-cast state by x-ray powder diffraction and scanning and high-resolution electron microscopy, as well as by low-temperature measurements of the magnetic susceptibility and specific heat. X-ray powder patterns of the alloys were indexed on the basis of a cubic primitive AuCu3 lattice throughout the entire solution showing a monotonous increase in three regimes. For 0x1.5, the volume increase corresponds merely to the substitution of Rh by Pd atoms, the sizes of which are rather close. In this regime the tetravalent character of cerium is unaffected. For x < 1.5, the lattice expansion becomes enhanced and is thus attributed to a gradual valence change of the Ce atoms (an intermediate valence regime). Finally, for x < 2.4, the system shows a predominant trivalent behavior. In this region, the specific heat coefficient reaches a value of 4.4 J mol-1 K2, two orders of magnitude larger than that in the Rh-rich border. Selected area electron diffraction patterns of the CeRh3-xPdxB0.5 compounds revealed the appearance of -type superstructures and satellite reflections with respect to the parent AuCu3 structure. Whereas the -type superstructure is confined to the Rh-rich part of the solid solution, satellite reflections are observed throughout the solid solution and hint towards the existence of a domain structure enclosed by anti-phase boundaries.Fil: Zeiringer, I.. University of Vienna; Austria. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche). División Bajas Temperaturas; ArgentinaFil: Sereni, Julian Gustavo Renzo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche). División Bajas Temperaturas; ArgentinaFil: Gomez Berisso, Mariano. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area de Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche). División Bajas Temperaturas; ArgentinaFil: Yubuta, K.. Tohoku University; JapónFil: Rogl, P.. University of Vienna; AustriaFil: Grytsiv, A.. University of Vienna; AustriaFil: Bauer, E.. Vienna University of Technology; Austri