We have studied the mechanical properties of niobium pentoxide and tantalum pentoxide ceramics prepared by a conventional ceramic processing technique and by exposure to high-intensity light (HIL). The results demonstrate that, after HIL exposure in an optical furnace, the niobium pentoxide and tantalum pentoxide ceramics possess enhanced microhardness and improved mechanical properties (strength, fracture toughness, and brittle microstrength) owing to the formation of fractal micro- and nanostructures. With increasing exposure intensity, the strength of the Nb₂O₅ and Ta₂O₅ ceramics increases.

Local polarization reversal and periodical domain structure engineering by an electron beam in the Z-cut of near-stoichiometric LiNbO₃ crystal (NSLN) was investigated. The NSLN was grown from a congruent composition containing 6%wt. K₂O flux by top-seeded solution growth method. The 0.75 mm thick Z-cut samples were irradiated in the SEM with a lithography system. Both −z and +z crystal sides were studied after selective etching using an optical microscope. The sideways and frontal domain wall motions at different densities of introduced e-beam charges were analyzed. Irradiation conditions for long triangular string-like domain reversal in the crystal plates of 750 µm thickness were determined. The domain gratings were fabricated in the same crystal plates by e-beam. In the bulk crystal, domain gratings (Λ = 10 µm) transformed to the 2D structure. The NSLN crystals hold promise for thick periodical domain structure engineering by e-beam technique.

GdNb_хTa_{1 –х}O₄ and YNb_хTa_{1 –х}O₄ (x = 0–1) ceramic samples have been prepared by a sol–gel process, and the luminescence properties of the solid solutions have been studied under UV excitation. The results demonstrate that even a relatively small amount of tantalum (x = 0.9) in GdNb_хTa_{1 –х}O₄ leads to a sharp increase in the luminescence intensity related to Nb⁴⁺–O^– centers, which exceeds the luminescence intensity in the GdNbO₄ and GdTaO₄ individual compounds by a factor of 3–6.5. The luminescence signal in the YNb_хTa_{1 –х}O₄ solid solutions exceeds that in the YNbO₄ and YTaO₄ end-members at any Nb : Ta ratio, owing to energy transfer between Nb⁴⁺–O^– and Ta⁴⁺–O^– emission centers.

The feasibility of synthesizing gadolinium tantalum niobates by the liquid-phase method was demonstrated. The methods of X-ray diffraction, electron probe microanalysis, local cathodoluminescence, and photoluminescence were applied to study the samples. It was shown that under the selected synthesis conditions (T ~ 1400°C for 3 hours), no solid solution of niobium-tantalum was formed in the powder samples. When obtaining ceramic samples, it was possible to obtain a solid solution and to study the dependence of the luminescence intensity on the niobium content upon excitation of the samples by an electron beam. The maximum luminescence intensity was observed in the sample with the composition of GdNb_0.9Ta_0.1O₄. It was shown that the inhomogeneity of luminescence is not related to fluctuations in composition, but is related to the inhomogeneous distribution of vacancy centers, which are luminescence centers.