Superhyperfine structure of F-, H-, D-, and T- charge-compensated Pr3+ centres CaF2 and SrF2 crystals

Abstract

Optical-RF double-resonance techniques have been used to study the superhyperfine transition frequencies in a series of Pr3+ centres in CaF2:Pr3+ and SrF2:Pr3+ crystals. In these centres Pr3+ substitutes for Ca2+ (Sr2+) and the excess positive charge is compensated by F-, H-, D- or T- interstitial ions along (100) directions yielding centres of C4v symmetry. The superhyperfine structure is associated with RF-induced nuclear spin flips of the lattice 19F- ions and of the interstitial ions that are coupled to the Pr3+ ion. Some qualitative conclusions are drawn about the position of the Pr3+ ion, the nearest-neighbour F- ions and the interstitial ions in the lattice.