Investigation of the trigonal-field splittings D and dependences on the local structural distortions for ZnSiF 6·6H 2O: Mn 2+ (Ni 2+)

Abstract

The local octahedral environments of the impurity ions in the ZnSiF 6·6H 2O: Mn 2+ (or Ni 2+) crystals with small axial (trigonal) distortions have been studied by analyzing their EPR spectra. According to the study, an interesting trend is suggested, i.e. the sign of the zero-field splitting (ZFS) D is in close relationship with the local structural distortions (elongation or compression) of the octahedral environment of the impurity ions. Thus, the bonding angles of distortions of the octahedral environments at low temperatures (4.2 K) are determined as θ − θ oh ≈ 0.344° and 0.055° for ZnSiF 6 · 6H 2O: Mn 2+ and ZnSiF 6 · 6H 2O: Ni 2+, respectively.