Popis: |
The magnetic properties of the ThMn 12 -type CeCu 4 Al 8 have been investigated by specific heat, magnetic susceptibility and electrical resistivity measurements. As we reported previously, CeCu 4 Al 8 is of an incongruent melt type. The specific heat for the CeCu 4 Al 8 sample annealed at 700°C (750°C) showed a large jump (peak) at 5.8 K (4.3 K), indicating the antiferromagnetic transition ( T N ), with a large C/T value of ∼ 0.3J/K 2 mol just above T N and ∼ 0.2J/K 2 mol at T → 0 (heavy fermion antiferromagnet). The resistivity showed a -log( T )-like increase below ∼ 50K and, after taking a gentle maximum at somewhat higher temperature than T N it decreased rather rapidly below T N with decreasing temperature. We have also investigated magnetic properties of the ThMn 12 -type CeCr 4 Al 8 and CeMn 4 Al 8 . The low-temperature specific heat showed large C/T of 0.18 J/K 2 mol for CeCr 4 Al 8 and 0.25 J/K 2 mol for CeMn 4 Al 8 , without any magnetic ordering. |