A new route to quantum critically in (U,Np)Pd-3

In the last couple of decades there has been considerable interest in the unique properties of matter in the vicinity of a quantum critical point, and therefore also in the mechanisms through which quantum phase transitions are generated. UPd3 is a canonical example of a system displaying long range antiferroquadrupolar order. We are investigating the evolution of the quadrupolar order in UPd3 with neptunium doping. We have found that the order is sensitive to low Np concentrations without the lattice being strongly disrupted, and anticipate that at some critical concentration the quadrupolar transition will be suppressed to zero temperature producing a quadrupolar quantum critical point. Here we present susceptibility and resistivity data for (U0.95Np0.05)Pd-3, which displays anomalous behaviour. (c) 2006 Elsevier B.V. All rights reserved.