Europhys. Lett.
Volume 69, Number 4, February 2005
Page(s) 577 - 582
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 26 January 2005
Europhys. Lett., 69 (4), pp. 577-582 (2005)
DOI: 10.1209/epl/i2004-10377-0

Disorder tuning of non-Fermi-liquid behaviour in $\chem{UCu_4Pd}$

P. Giudicelli1, 2, U. Killer3, J. W. Taylor4, S. J. Levett4, A. Otop5, E.-W. Scheidt3, A. Stunault2 and N. Bernhoeft1

1  DRFMC, CEA-Grenoble - F-38054 Grenoble, France
2  Institut Laue Langevin - F-38042 Grenoble, France
3  Institut für Physik, Universität Augsburg - D-86159 Augsburg, Germany
4  ISIS Facility, RAL - Didcot, Oxfordshire, UK
5  Institut für Physik, TU Braunschweig - D-38106 Braunschweig, Germany

received 22 September 2004; accepted in final form 7 December 2004
published online 26 January 2005

Neutron inelastic scattering has been used to examine the space-time magnetic correlation function in the non-Fermi-liquid compound $\chem{UCu_4Pd}$. In contrast with the results obtained previously on as-cast samples, the response of carefully annealed material shows a simple exponential time dependence. These microscopic measurements confirm an earlier conjecture based on annealing experiments that, whilst atomic disorder is not the origin of non-Fermi-liquid behaviour in $\chem{UCu_4Pd}$, the order-disorder equilibrium may, however, in a similar manner to the use of applied magnetic field, pressure and composition, be used as a tuning parameter to achieve non-Fermi-liquid response.

71.10.Hf - Non-Fermi-liquid ground states, electron phase diagrams and phase transitions in model systems.
71.27.+a - Strongly correlated electron systems; heavy fermions.
75.20.Hr - Local moment in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions.

© EDP Sciences 2005