Letters to Nature

Nature 407, 351-355 (21 September 2000) | doi:10.1038/35030039; Received 18 April 2000; Accepted 26 July 2000

Onset of antiferromagnetism in heavy-fermion metals

A. Schröder1, G. Aeppli2, R. Coldea3,4, M. Adams4, O. Stockert1,5, H.v. Löhneysen1, E. Bucher6,7, R. Ramazashvili8 & P. Coleman9

  1. Physikalisches Institut, Universität Karlsruhe, D-76128 Karlsruhe, Germany
  2. NEC, 4 Independence Way, Princeton, New Jersey 08540, USA
  3. Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
  4. ISIS Facility, CCLRC, Rutherford-Appleton Laboratory, Didcot OX11 0QX, UK
  5. Department of Physics, University of Konstanz, D-78457 Konstanz, Germany
  6. Bell Laboratories, Lucent Technologies , Murray Hill, New Jersey 07974, USA
  7. Department of Physics, University of Illinois, Urbana, Illinois 61801, USA
  8. Center for Materials Theory, Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA
  9. Present address: H.H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL, UK.

Correspondence to: P. Coleman9 Correspondence and requests for materials should be addressed to P.C. (e-mail: Email: Coleman@physics.rutgers.edu).

There are two main theoretical descriptions of antiferromagnets. The first arises from atomic physics, which predicts that atoms with unpaired electrons develop magnetic moments. In a solid, the coupling between moments on nearby ions then yields antiferromagnetic order at low temperatures1. The second description, based on the physics of electron fluids or 'Fermi liquids', states that Coulomb interactions can drive the fluid to adopt a more stable configuration by developing a spin density wave2, 3. It is at present unknown which view is appropriate at a 'quantum critical point', where the antiferromagnetic transition temperature vanishes4, 5, 6, 7. Here we report neutron scattering and bulk magnetometry measurements of the metal CeCu6-xAux, which allow us to discriminate between the two models. We find evidence for an atomically local contribution to the magnetic correlations which develops at the critical gold concentration (xc = 0.1 ), corresponding to a magnetic ordering temperature of zero. This contribution implies that a Fermi-liquid-destroying spin-localizing transition, unanticipated from the spin density wave description, coincides with the antiferromagnetic quantum critical point.