Drastic annealing effects in transport properties of single crystals of the YbNi2B2C heavy fermion system

[摘要] We report temperature-dependent resistivity, specific heat, magnetic susceptibility, and thermoelectric power measurements made on the heavy fermion system YbNi2B2C, for both as-grown and annealed single crystals. Our results demonstrate a significant variation in the temperature-dependent electrical resistivity and thermoelectric power between as-grown crystals and crystals that have undergone optimal (150 h, 950 degreesC) annealing, whereas the thermodynamic properties [c(p)(T) and chi(T)] remain almost unchanged. We interpret these results in terms of redistributions of local Kondo temperatures associated with ligandal disorder for a small (similar to1%) fraction of the Yb sites.

[关键词] MAGNETIC SUPERCONDUCTORS;FIELD