Ferromagnetic quantum critical point in URhGe doped with Ru

We have investigated the thermal, transport, and magnetic properties of URh1-xRuxGe alloys near the critical concentration x(cr)=0.38 for the suppression of ferromagnetic order. The Curie temperature vanishes linearly with x and the ordered moment m(0) is suppressed in a continuous way. At x(cr), the specific heat varies as c similar to T ln T, the gamma value c/T parallel to(0.5 K) is maximum, and the temperature exponent of the resistivity rho similar to T-n attains a minimum value n=1.2. These observations provide evidence for a ferromagnetic quantum phase transition. Interestingly, the coefficient of thermal expansion and the Gruneisen parameter Gamma remain finite at x(cr) (down to T=1 K), which is at odds with recent scaling results for a metallic quantum critical point.