Distortion of the Local Atomic Structure of Nb5+ and Fe2+ Ions in Fe:LiNbO3 Crystals

High frequency ultrasonic waves in the 200–300 MHz range are used to study features of charged complexes organized by O2– ions around Jahn–Teller ions Nb5+ and Fe2+ in congruent crystals of LiNbO3 doped with Fe2+. Parameters of the distortion of NbO6 and FeO6 octahedra that results from the interaction between Jahn–Teller ions and the host crystal lattice are determined from the temperature characteristics of changes in the elastic moduli.