Systematics of mixed valence and heavy fermion behaviors in YbCu5 and related systems

Composition dependence of the Yb-valence transition has been investigated i n the several Yb systems substituted for Yb, In and Cu sites in YbInCu4. It has been found that the transition temperature T-v and the transition magn etic field H-v are affected markedly by the substitution. The volume (chemi cal pressure) effect, the dense Kondo interaction and the band hybridizatio n are discussed as factors which determine T-v and H-v in these substituted systems. (C) 2000 Published by Elsevier Science B.V. All rights reserved.