Abstract
Elastic moduli, specific heat, magnetic susceptibility and electrical resistivity have been measured for single-crystalline Kondo compounds CeRhIn and CeRhSn with the hexagonal ZrNiAl-type structure. Most of the previous works reported that both compounds have a valence fluctuation state. However, our results show that 4f electrons in CeRhSn have a localized nature whereas in CeRhIn, they show valence fluctuation. The elastic moduli and specific heat suggest that in CeRhSn, a crystal electric field plays a significant role in addition to a Kondo effect with Kondo temperature TK≈40 K. In CeRhIn, elastic, thermal, magnetic and transport properties can be understood by a renormalized two-band model with TK≥300 K.