Pseudogap due to Coherence Kondo Effect in CeNiSn and CeRhSb

Abstract

Specific heat of single crystal of CeNiSn has been measured between 1.3 and 60, K and analyzed together with that of polycrystals of CeRhSb, CeNi_1-xPt_xSn (x=0.03, 0.06, 0.12 and 0.20) and CeNi_1-yCo_ySn (y=0.03 and 0.10). The magnetic specific heat divided by temperature C_m/T of CeNiSn and CeRhSb exhibits a maximum and substantially decreases at low temperatures indicating the energy gap opening in the heavy quasiparticle band. The Kondo temperatures T_K were estimated to be 51, K for CeNiSn and 89, K for CeRhSb by fitting the magnetic entropy S_m. Using the reduced temperature ˜{T}=T/T_K, C_m/T was plotted in C_m/˜{T} versus ˜{T}. The plot reveals the obvious relation between the energy gap formation and the Kondo effect.