Influence of Mg doping on refractive index of LiNbO3 crystals

Rapid response of photorefraction in vanadium and magnesium co-doped lithium niobate

“…The refractive index change (Δn) depends on electrooptic coefficients (r 33 ) and refractive index (n o , n e ) which varies with Li vacancies and Mg-doping concentraion in LN especially above 2 mol%. The anomalies in electro-optic coefficient values and refracitve index occur in LN:Mg crystals with increase of Mg-doping concentration [28][29][30][31]. We think that the changes in diffraction efficiencies on doping concentration may arise from the variation in the value of these parameters, too.…”

EFFECT OF MgO DOPING ON COERCIVE FIELD IN LiNbO3 CRYSTALS

“…The distance between the oxygen ions lying in the face closest to the lithium ion is greater (3.362Å) than the corresponding distance of Nb (1.39Å) from oxygen octahedral. 17 Abrahams et al 18 have pointed out that the specific position of the metal ions gives rise to spontaneous polarization. The direction of the displacement of the cations determines the direction of the spontaneous polarization vector in the ferroelectric phase of LN crystal.…”

“…The effective ionic charges of Li and Nb cations have been calculated by following Granovsky's approach, 17 where he treated CLN as an ABO 3 type Perovskite crystal, and each atom A (Li) and B (Nb) in their corresponding lattice is assigned to a formal average effective electronegativity defined by E A and E B , respectively. The electronegativity of the impurity ion Mg modifies the changes in effective charges at A (Li) and B (Nb) sites due to a change in the average effective electronegativity of the cationic octahedra according to its substitution mechanism.…”