The 1-K phase transition in UCu5, showing up in specific-heat data within the antiferromagnetic state below TN$\simeq$15 K, was investigated. Neither the average internal fields seen by the $\mu$+ nor the magnetic and nuclear Bragg reflections in the neutron-diffraction data reflect the phase transition while the muon relaxation rates increase drastically below 1.2 K. These results are interpreted in terms of some additional small-moment magnetic order or spin-density-wave phenomenon, implying the coexistence of two rather independent electronic subsystems, one involving ``heavy'' electrons, associated with the weak magnetism, and the other associated with the ``conventional'' antiferromagnetic order.     «

The 1-K phase transition in UCu5, showing up in specific-heat data within the antiferromagnetic state below TN$\simeq$15 K, was investigated. Neither the average internal fields seen by the $\mu$+ nor the magnetic and nuclear Bragg reflections in the neutron-diffraction data reflect the phase transition while the muon relaxation rates increase drastically below 1.2 K. These results are interpreted in terms of some additional small-moment magnetic order or spin-density-wave phenomenon, implying t...     »