Kondo Effects and Multipolar Order in the cubic PrTr2Al20 (Tr=Ti, V)

Our single crystal study reveals that PrTr2Al20 (Tr = Ti and V) provides the first examples of a cubic Γ3 nonmagnetic ground doublet system that shows the Kondo effect including a− lnT dependent resistivity. The Γ3 quadrupolar moments in PrV2Al20 induce anomalous metallic behavior through hybridization with conduction electrons, such as T 1/2 dependent resistivity and susceptibility below ∼ 20 K down to its ordering temperature TO = 0.6 K. In PrTi2Al20, however, quadrupoles are well-localized and exhibit an order at TO = 2.0 K. Stronger Kondo coupling in PrV2Al20 than in PrTi2Al20 suppresses quadrupolar ordering, and instead promotes hybridization between the Γ3 doublet and conduction electrons, leading to most likely the quadrupolar Kondo effect.