Strongly Correlated Electron Behaviour in CeT2Al8 (T = Fe, Co)

We report on studies of physical properties of the two compounds CeFe2Al8 and CeCo2Al8 in which we have found varying degrees of electronic correlational phenomena. No magnetic ordering was detected down to 0.4 K in either of the two compounds. At elevated temperatures an incoherent Kondo interaction between the Ce 4f-electron and the conduction electrons is prevalent in both compounds. CeCo2Al8 exhibits a stable 4f-electron magnetic moment, but in CeFe2Al8 an intermediate-valent state prevails near room temperature that eventually transforms into a Fermi-liquid ground state. The low-temperature specific heat of CeCo2Al8 shows typical strongly correlated electron behaviour and a - log T upturn in its electronic specific heat below about 10 K.