Ultrafast dynamics of the heavy fermion state in UX/sub 3/ compounds

Summary form only given. The uranium compounds UX/sub 3/, crystallize in the cubic AuCu/sub 3/-type structure. Due to the wide range of f electron-ligand (X) hybridization strength in these compounds, they exhibit a wide range of behavior: Pauli enhanced paramagnetism (UAl/sub 3/, USi/sub 3/, and UGe/sub 3/), antiferromagnetism (UGa/sub 3/, UPb/sub 3/, and UIn/sub 3/), heavy fermion behavior (USn/sub 3/) and superconductivity (URu/sub 3/). The interaction of the partially filled f shell electrons with the conduction electrons causes the mass renormalization of the latter and the formation of heavy quasiparticles. We investigate the dynamics of this renormalization in UX/sub 3/ compounds, where X=Al, Ga, Sn with electronic specific heat coefficients (/spl gamma/) of 43 mJ/molK/sup 2/, 52 mJ/molK/sup 2/, and 172 mJ/molK/sup 2/ respectively, (as compared to /spl gamma//spl sim/1 mJ/molK/sup 2/ for ordinary metals such as Cu). The single crystals of UX/sub 3/ were grown using a standard flux technique.