THE NORMAL STATES OF MAGNETIC-D AND MAGNETIC-F TRANSITION-METALS

The normal states of magnetic metals with vanishing Curie (T-c) or Nee l (T-N) temperatures are investigated by means of measurements of the temperature and pressure dependence of the resistivity in the stoichio metric d and f compounds MnSi, ZrZn2, CePd2Si2 and CeNi2Ge2. The resul ts for the nearly ferromagnetic d metals may be described over a wide range in temperature and pressure in terms of a quantitative model of a marginal Fermi liquid based on dispersive spin-fluctuation spectra i nferred from inelastic neutron scattering data. The behaviour of the a ntiferromagnetic f metals is also unconventional, but in a way which c annot yet be readily categorized. Near the critical pressure where T-N --> 0 K, CePd2Si2 displays a resistivity of the form rho similar to T -1.2+/-0.1 over nearly two decades in temperature before condensing in to a short-coherence-length superconducting state below 0.4 K. The iso electronic and isostructural compound CeNi2Ge2, with a lattice cell vo lume slightly smaller than that of CePd2Si2, remains normal down to 20 mK and shows a resistivity of the form rho similar to T-1.4+/-0.1 ove r a decade below several kelvin at ambient pressure. These findings fo r the Ce systems have not yet been described consistently in terms of an extension of the model developed for the ferromagnetic d metals.