“…We have compared obtained results with data on nominally pure congruent (LiNbO 3 ) and stoichiometric (LiNbO 3 ℎ ) crystals. Optical absorption spectra, conductivity, PILS and photoelectric fields were previously researched for some of these LiNbO 3 crystal compounds in papers[3,[12][13][14][15][16][17][18][19].…”