Size-induced transition from magnetic ordering to Kondo behavior in (Ce,Al) compounds

Magnetic ordering and Kondo behavior coexist in three (Ce,Al)-based compoun ds: CeAl2, Ce3Al, and Ce3Al11. A common feature apparently independent of c rystal structures also prevails in terms of the size-induced transition bet ween these two magnetic phenomena. As the particle size is reduced to nanos cale, the specific heat anomaly associated with the magnetic ordering dimin ishes. Although the Kondo temperature also decreases, the entropy associate d with Kondo anomaly exhibits a large increase. This results in an enhancem ent of the Kondo behavior and an increased coefficient gamma of the linear term in specific heat. For example, in 80 Angstrom CeAl2 the extrapolated r (0) reaches 9000 mJ mol Ce-1 K-2.