Formation of a Hybridization Gap in a Cage-Like Compound CeFe₂Al₁₀

Abstract

We report on the magnetic, transport, and thermal properties of a cage-like compound CeFe2Al10 that crystallizes in the orthorhombic YbFe2Al10-type structure. A broad peak in the magnetic susceptibility at 70 K indicates that CeFe2Al10 is a valence fluctuation compound. The electrical resistivity and the Hall coefficient exhibit sharp upturns below 20 K, where the thermopower shows a rapid decrease. These low-temperature anomalies in the transport properties resemble those of a typical Kondo semiconductor CeRhSb. These features indicate the formation of a hybridization gap in CeFe2Al10 on cooling below 20 K. The energy gap is estimated as 15K from the thermal activation energy of the resistivity. The magnetic contribution of the specific heat shows a Schottky-type maximum at 30 K that provides another evidence for the gap formation in CeFe2Al10.