Valence behavior of Eu-ions in intermetallic compound Ce0.5Eu0.5Pd3B0.5Ce0.5Eu0.5Pd3B0.5

We have studied the valence behavior of rare-earth ions, in particular Eu-ions, in a cubic intermetallic compound Ce0.5Eu0.5Pd3B0.5Ce0.5Eu0.5Pd3B0.5 which is a homogeneous solid solution of two mixed-valent compounds CePd3 and EuPd3BEuPd3B. Results of 151Eu Mössbauer spectroscopic measurements show that two different valence states, i.e., divalent- and trivalent-like states of Eu-ions exist in the compound. The possible reason for the observed heterogeneous valency vis-á-vis the variation in the chemical environment and the number of nearest-neighbor B atoms surrounding the Eu-ions has been discussed. Our results demonstrate that B incorporation in such Eu-based cubic intermetallic compounds leads to a situation where heterogeneous-valence state of Eu-ions is an energetically favorable ground state.

► Intermetallic compound Ce0.5Eu0.5Pd3B0.5 crystallizes in a single phase.
► Eu-ions in Ce0.5Eu0.5Pd3B0.5 are charge-ordered compared to +2.3 valency in Ce0.5Eu0.5Pd3.
► B incorporation makes charge-ordered state of Eu-ions energetically more favorable.
► Nearest-neighbor chemical environment affects the Eu valency.