Charge transfer and155Gd isomer shift in various intermetallic compounds of Gd

Abstract

The isomer shift observed by means of 155Gd Mossbauer spectroscopy in intermetallic compounds composed of Gd and one of the metals M=Al, In, Pb, Sn, Zn, Cu, Ni, Co, Fe or Mn was analysed in terms of a model proposed earlier for the 197Au isomer shift in Au based materials by Miedema and van der Woude (1980). In combining Gd with s, p metals (Al, In, Zn, Pb, Sn) the s electron character at the Gd sites is decreased while the d electron character is increased. Upon compounding Gd with Cu or 3d metals, both the s and d electron characters are decreased. In the cubic C15 type compounds RM2, the decrease of the d character is strong in particular when M is Ni, Co or Fe. For most of the compounds investigated the 155Gd hyperfine fields were also determined.