The photoluminescence (PL), its excitation (PLE) and absorption spectra in ultraviolet, visible and infrared (UV-VIS-IR)
regions were used to investigate the MgO single crystals irradiated by fast neutrons. It is shown that the
photoluminescence band of the MgO crystals at 730 nm belongs to the hydrogen-containing complex centers V<sup>-</sup><sub>OH</sub>-Fe<sup>3+</sup>, which are transformed during the irradiation with fast neutrons. The behavior of the PL band 730 nm after fast neutron
irradiation depends on the iron-chromium concentration. It is found that the fast neutron irradiation produces the
interstitial proton H<sup>+</sup><sub>i</sub> and the Mg(OH)<sub>2</sub> microphase.
Influence of radiation defects on the optical absorption spectrum of nickel oxide (NiO) was studied at 6 K in the near-IR
energy range of 7750-8300 cm<sup>-1</sup> corresponding to the magnetic-dipole transition <sup>3</sup><i>A</i><sub>2g</sub>(<i>F</i>)-><sup>3</sup><i>T</i><sub>2g</sub>(<i>F</i>) at nickel sites. NiO
single crystals grown by the method of chemical transport reactions on the MgO(100) substrates were irradiated by the
neutron fluences up to 5x10<sup>18</sup> cm<sup>-2</sup>. Two sharp lines were observed at the low-energy side of the band: the peak at
7805 cm<sup>-1</sup> is assigned to the pure exciton transition, whereas the peak at 7845 cm<sup>-1</sup>, to the exciton-magnon excitation that
occurs at the Brillouin zone-center (BZC). An increase of the defect concentration at higher fluences results in the
lowering of the magnon-satellite-peak intensity. The long-wavelength BZC magnon absorption is sensitive to the long-
range magnetic ordering, which becomes destroyed in the presence of the radiation defects. Therefore, the observed
decrease of the peak intensity is attributed to the decrease of the spin-spin correlation length due to inhomogeneous
Coatings of AlN, TiN and nanostructured multilayer AlN/TiN have been deposited by reactive sputtering on sapphire, tungsten carbide (WC) and stainless steel substrates. The microhardness, adhesion and formation of cracks under indentation tests, were investigated. It was found that the adhesion of coatings on steel was higher, than on WC for all investigated samples. Nanostructured multilayer AlN/TiN films have the best adhesion and fracture toughness both on the hard (WC) and on the soft (stainless steel) substrates if compared with that for AlN and TiN "single layer" coatings. The effect of γ-radiation on mechanical properties of transparent AlN films was investigated. After the exposure of γ-radiation (10<sup>6</sup> Gy) the microhardness of AlN has increased by 33%. No debonding or destruction of AlN films under irradiation was observed.
The present work summarizes the results of absorption and luminescence spectra investigation of natural and synthetic magnesium aluminum spinels (MgO*nAl<SUB>2</SUB>O<SUB>3</SUB>) containing chromium and manganese ions. The spectra have been analyzed with an aim to determine the effect of stoichiometry 'n' on distribution of emitting ions. The Mn<SUP>2+</SUP> is observed in both tetrahedral and octahedral coordinations providing green or orange emission. Absorption bands have been explained in terms of the Mn<SUP>2+</SUP> configuration model. Laser excitation of chromium-comprising magnesium aluminum spinel crystals has been carried out at 7 K with the purpose to detect the nearest neighbors of Cr<SUP>3+</SUP> ions. Luminescence emission spectra have been obtained for natural sample and three synthetic samples (MgO*nAl<SUB>2</SUB>O<SUB>3</SUB>, n equals 1, 2, 2.8). Decay time has been measured at different wavelengths and compared for crystals of different stoichiometry. In case n equals 2 or 2.8, computer simulation has been used to decompose smeared luminescence spectra in the 680 - 700 nm region. Gaussian curves corresponding to R- and N-lines of natural spinel spectrum have been applied as components in the calculations of nonstoichiometric spinel spectra. This suggests that there aren't normally arranged Cr-occupied octahedral positions in nonstoichiometric spinel (n equals 2.8, e.g.).