Semiconducting behavior in CeFe₂Al₁₀and CeRu₂Al₁₀single crystals

Abstract

We have firstly succeeded in growing orthorhombic YbFe2Al10-type CeFe2Al10 and CeRu2Al10 single crystals by Al self-flux method, and measured the electrical resistivity ρ and magnetic susceptibility χ. Both compounds show negative temperature coefficient in ρ above ~100 K. The ρ(T) of CeFe2Al10 shows a broad peak at around 100 K and increases again at low temperatures, suggesting semiconducting ground state. The ρ(T) of CeRu2Al10 shows an abrupt increase below T0=27.3 K and and metallic behavior at low temperatures. The χ(T) exhibits uniaxial magnetic anisotropy along the b-axis for CeFe2Alio and c-axis for CeRu2Al10. CeRu2Al10 shows a sudden drop at T0 in χ(T), indicating some kind of phase transition at T0- Since both compounds have smaller cell volumes than those expected from lanthanoid contraction, these anomalous behaviors should be related to the strong 4f- and conduction-electron hybridization.