Single crystal growth of CeNi2 Ge2 using the floating zone technique

In order to investigate the low-temperature electronic properties of the heavy-fermion metal CeNi 2 Ge 2 , single crystals were grown using the floating zone technique. Previous investigations on polycrystals of CeNi 2 Ge 2 have revealed that the low-temperature properties, i.e., non-Fermi liquid (NFL) behavior and incipient superconductivity, are strongly sample dependent, possibly due to a slight variation of the Ni and Ge content. We prepared polycrystalline feed rods of slightly off-stoichiometric composition by induction or arc-melting methods and grew single crystals using a four-mirror optical furnace under high-purity argon atmosphere. As a result, large single crystals of few centimeter size have been obtained. Annealed pieces were investigated by measurements of the temperature dependence of the electrical resistivity ρ(T). A clear correlation between the starting composition and the obtained resistivity ratio (RR 2K ) was found with the highest ratio for a nominal starting composition of Ce 0.98 Ni 2.025 Ge 1.975 (RR 2K = 29). The temperature dependence of the electrical resistivity is similar as reported previously and displays NFL behavior below 1 K.