Electronic properties of a heavy-fermion U(Ru_0.92Rh_0.08)₂Si₂ single crystal

We report the crystal structure and highly anisotropic magnetic, transport, and thermal properties of an exceptionally good single crystal of U(Ru_0.92Rh_0.08)₂ Si₂, prepared using a modified Czochralski method. Our study, that also includes neutron diffraction results, shows all the heavy-fermion signatures of pristine URu₂Si₂; however, the superconductivity, hidden order, and remnant weak antiferromagnetic orders are absent. Instead, the ground state of the doped system can be classified as a spin liquid that preserves the heavy-fermion character. U(Ru_0.92Rh_0.08)₂ Si₂ exhibits a short-range magnetic order distinguished by reflections of a Lorentzian profile at qIII=(½ ½ ½) positions that disappear above ∼15 K. The short-range order seems to be a precursor of a long-range magnetic order that occurs with higher Rh concentration. We indicate that these short-range fluctuations involve, at least partially, inelastic scattering processes.