The onset of magnetism in CeNi1-xTxSn (T = Cu, Pt)

Magnetic order (including spin freezing) is absent down to similar to 15 mK in CeNiSn due to the dominance of coherent spin fluctuations caused by the Kondo interaction. Partial replacement of Ni by Cu or Pt induces a highly disordered magnetic state. The critical concentration is much lower for Cu replacement (similar to 7%) than for Pt replacement (similar to 30%). Resul ts of mu SR and specific heat (for CeNi1-xCuxSn) measurements near the crit ical concentration are presented. The possibility of a quantum critical poi nt is discussed. A tentative phase diagram for the two parameters relevant for the onset of magnetism, the unit cell volume and the d electron density , is derived. (C) 2000 Published by Elsevier Science B.V. All rights reserv ed.