A new analytical description in C 2+ doped LiBO 3 C (Ni, Zn…); B (Nb, Ta)

Defect structure models for C-doped non-stoichiometric lithium niobate and lithium tantalate were generally based on the defect model proposed for undoped crystals i.e. Li-site vacancy or Nb-site vacancy descriptions. The atomic radius of C is r C = 135 pm. This work is an extension of the Safaryan theory. A new analytical description has been proposed. It is based on the vibrations of crystal planes. The substitution mechanism of the doped compositions C in LiBO3 crystal is discussed. The mechanism of phase transition due to thermal expansion of crystal is also described.