Effect of stoichiometry on the dynamic mechanical properties of LiNbO3

Abstract

Articles you may be interested inIntrinsic anomalous ferroelectricity in vertically aligned LiNbO3-type ZnSnO3 hybrid nanoparticle-nanowire arrays Appl. Phys. Lett. 105, 212903 (2014); 10.1063/1.4902557 40-50MHz lithium niobate (LiNbO3) transducers for pulsed Doppler measurements in mouse embryos Acoustic and optic phonons have been measured by Brillouin and Raman spectroscopies in LiNbO 3 samples with different stoichiometries. Consequently, the elastic constants have been determined by Brillouin scattering as a function of the stoichiometry. The C 44 elastic constant presents, as a function of the stoichiometry, a clear minimum for the ͓Li͔/͓Nb͔ϭ1 in the melt sample. This behavior must be related to the existence and competition of two kind of defects, i.e., extended defects induced when growing samples not at the congruent composition, and point defects present in nonstoichiometric samples. The optic phonons seem to be dominated by the point defects. The linear increase of the phonon lifetimes, with respect to an ideal stoichiometric sample, can be due to the scattering by the static imperfections and to an increase of the anharmonic scattering. Several Raman peaks, which appear when the ͓Li͔/͓Nb͔ ratio decreases, are related to the presence of Nb in antisites. The width of some particular phonons can be used to estimate the ͓Li͔/͓Nb͔ ratio whenever a line shape study and a good correction, taking into account the instrumental broadening, is carried out.

Characterization of structural and photoinduced defects in pure and doped lithium niobate

“…From these data, using best fit procedure with lorentzian curve to interpolate the data, we obtain line width parameters (reported in Table 1) for the above mentioned E and A modes. The values are very close to those reported in previous works [6][7][8] confirming nominal stoichiometry and evidencing a low structural disorder degree. In addition, at this amount, iron doping does not induce marked Raman modes broadening.…”

“…In LN the line width of some Raman lines (E(TO) mode at ∼150cm -1 and A 1 mode at ∼ 870cm [6][7][8]. Additional information about disorder arising in the ferroelectric chains Nb-O can be obtained from weak and broadened features in the spectra between 550-800cm -1 [9,10].…”

Study on Ag doping in congruent lithium niobate crystal

“…For example, the lowest soft A 1 1 mode was suggested being sensitive to Nb-site defect, while the A 2 1 mode being sensitive to the imperfection of Li-site. In addition, the A 4 1 mode was found to consist of three lines, which have been attributed to Nb vacancy V Nb -O, normal Nb-O and Nb Li -O bonds, respectively [17]. From Fig.…”

“…The fitted peaks are labeled in Fig. 3 according to the Raman peak assignment reported before [16,17], and the fitted parameters are listed in Table 1.…”

Structural and optical properties of hafnium‐doped lithium‐niobate crystals

“…It has been demonstrated that the linewidth of some Raman lines can be correlated to the composition x c = [Li/(Li+ Nb)] of the LiNbO 3 crystal [7][8][9]. In addition, Raman data have also been utilized to elucidate the mechanism of Mg ion incorporation in the defective LN lattice or the role of H in disordering the ferroelectric chain Nb-O after proton exchange [10,11].…”