Regensburg 2010 – wissenschaftliches Programm

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TT: Fachverband Tiefe Temperaturen

TT 26: CE: Heavy Fermions

TT 26.5: Vortrag

Mittwoch, 24. März 2010, 15:00–15:15, H21

Investigation of the metamagnetic transition in Ce_1−xLa_xTiGe polycrystals — •Micha Deppe, Nubia Caroca-Canales, Franziska Weickert, Stefan Lausberg, Manuel Brando, Christoph Geibel, and Frank Steglich — Max-Planck-Institute for Chemical Physics of Solids, 01187 Dresden, Germany

CeTiGe is a new heavy Fermion system with a Kondo energy scale of the order of 50 K. Our investigations of the specific heat, magnetic susceptibility and resistivity of polycrystals evidenced a paramagnetic heavy Fermi liquid with a Sommerfeld coefficient γ₀ ≈ 300 mJ/molK² at low temperatures. The temperature dependence of the susceptibility and of the specific heat reveal a maximum at 24 K and 16 K, respectively, indicating that the full J = 5/2 state of Ce³⁺ is involved in the formation of the heavy Fermion ground state [1].
DC magnetization measurements at 1.8 K up to 14 T on pure CeTiGe showed a step like increase of the magnetization ΔM ≈ 0.7 µ_B/Ce at B_MM ∼ 13.5 T, which evidences a pronounced metamagnetic transition (MM). Here we shall focus on the development of the MM phase boundary in Ce_1−xLa_xTiGe upon increasing La content using ρ(B) and M(B) measurements. The observation of a hysteresis in ρ(B) and M(B) at B_MM for Ce_1−xLa_xTiGe, which vanishes at x = 0.6, is a strong hint for a first order phase transition, in contrast to the crossover behavior reported for CeRu₂Si₂[2]. Thus the metamagnetic transition in CeTiGe represents a unique case among Kondo lattice systems.

[1] M. Deppe et al. J. of Phys.: Condensed Matter 21, (2009) 206001.

[2] P. Haen et al. J. of Low Temp. Phys. 67 (1987).