Measurements of the electrical resistivity, magnetoresistance, ac and dc magnetic susceptibility and specific heat on YbBiPt indicate this compound to be a IveryP heavy-electron system. The low-temperature Sommerfeld coefficient of 8 J/K2 (mole Yb) is not affected by a phase transition at 0.4 K. We suggest that the heavy-mass state in YbBiPt is unconventional in that it develops from Bloch states in an electronic subsystem with low carrier concentration. © 1991 The American Physical Society.

YbBiPt has a low temperature linear specific heat coefficient of 8 J/mol Yb K2 and a small specific heat anomaly at 0.4 K. We discuss new experiments on the specific heat of diluted YbBiPt, magnetic field dependent effects and electrical resistivity in pure YbBiPt. We argue that in this material the Kondo and crystal field energy scales are small and of comparable magnitude, placing YbBiPt in the same class as many uranium heavy electron compounds. © 1993.