We have investigated the thermal, transport, and magnetic properties of $\mathrm{U}{\mathrm{Rh}}_{1-x}{\mathrm{Ru}}_x\mathrm{Ge}$ alloys near the critical concentration $x_{\mathit{cr}}=0.38$ 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 $x_{\mathit{cr}}$, the specific heat varies as $c\sim T\ln T$, the $\gamma$ value ${\phantom{\mid }c∕T\mid }_{0.5\mathrm{K}}$ is maximum, and the temperature exponent of the resistivity $\rho \sim T^n$ 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 Grüneisen parameter $\Gamma$ remain finite at $x_{\mathit{cr}}$ (down to $T=1\mathrm{K}$), which is at odds with recent scaling results for a metallic quantum critical point.

• Received 13 March 2007

DOI:https://doi.org/10.1103/PhysRevB.75.212405

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