G roup Activities Research Group for Condensed Matter Physics of Heavy Element Systems

In heavy element (f-electron) systems, valence fluctuations, the Kondo effect, and the RKKY interaction compete with one another. Because of this, exotic behaviors such as quantum critical points, heavy fermions, non-Fermi liquids, anisotropic superconductivity and multipolar ordering appear when such competition is strong. Recently, it has become clear that these exotic behaviors for 5f-electron systems are different from those for 4f-electrons. This is because electrons with different spin and orbital character can coexist in 5f actinide systems, in contrast to the case of 4f electrons. By means of microscopic spectroscopy: NMR and μSR, our research group tries to clarify these exotic behaviors due to the “many-fold ” character of both 4f and 5f compounds, including transuranium. Non-collinear antiferromagnetic ordering and new type of multipolar frustration in TbCoGa