Dresden 2006 – wissenschaftliches Programm

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TT: Tiefe Temperaturen

TT 25: Correlated Electrons - Poster Session

TT 25.59: Poster

Mittwoch, 29. März 2006, 14:30–18:30, P1

Hall effect near the quantum critical point of CeCu_6−xAu_x — •M. Röger¹, M. Uhlarz¹, S. Putselyk¹, O. Stockert², and H. v. Löhneysen^1,3 — ¹Physikalisches Institut, Universität Karlsruhe (TH), D-76128 Karlsruhe — ²Max-Planck-Institut für chemische Physik fester Stoffe, D-01187 Dresden — ³Forschungszentrum Karlsruhe, Institut für Festkörperphysik, D-76021 Karlsruhe

The heavy-fermion system CeCu_6−xAu_x orders antiferromagnetically above x_c = 0.1. The quantum phase transition at x_c displays unusual features, e.g., low-dimensional spin fluctuations and locally critical slowing down of these spin fluctuations suggestive of a breakdown of the Kondo coupling between 4f and conduction electrons [1]. This breakdown should be reflected in the Hall effect [2]. The Hall effect of CeCu_6−xAu_x (0 ≤ x ≤ 0.2) as measured in a finite field (B = 0.3 T) along the magnetically easy c axis has shown Fermi-liquid behavior at low T, i.e. a temperature-independent Hall constant R_H below ∼ 0.3 K [3]. Applying the magnetic field parallel to the magnetically hard b-axis (anisotropy factor ∼ 10) allows to detect the effect of magnetic order on R_H for x = 0.2 and of quantum criticality for x = 0.1.

[1] A. Schröder et al., Nature 407, 6802 (2000)

[2] P. Coleman et al., J. Phys. Cond. Matt. 13, R723 (2001)

[3] H. Bartolf et al., Physica B 359-363, 86 (2005)