Analysis for Softening of Elastic Constant and Specific Heat in CePd₂Al₃ - Quadrupole Response Induced by the Kondo Effect -

Abstract

We analyze the temperature dependence ofthe specific heat and the quadrupole susceptibilityfor CePd_2Al_3, in which the Kondo effect coexistswith the crystalline electric field (CEF) excitation.The calculation is carried out systematicallyby using the numerical renormalization group method.The ratio Δ / T_k^o(Δ: the CEF excitation energy, T_k^o: the Kondo temperature for the fictitious system of Δ= 0)is estimated to be about 1.2 from the data of magnetic specific heat.The observed softening of C₃₃ mode at very low temperature, which is expected to vanish in hexagonal compound such as CePd₂Al₃from the conventional CEF theory, is explained by considering the Kondo effect.