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The effect of a photostimulated solid state reaction was investigated in Mn doped SrTiO3 samples. Light irradiation was performed by either halogen or UV lamps in order to study the effect of the spectral composition, and the results were compared with samples prepared at the same temperatures in a conventional furnace. The obtained samples were studied by X-ray diffraction for structural characterization and by Electron Paramagnetic Resonance, which provides microscopic information about the local environment as well as the valence state of Mn ions. It was found that light irradiation significantly enhances the solid state reaction rate compared to synthesis in the conventional furnace. Moreover, it was observed that UV lamp irradiation is much more effective compared to halogen lamps. This indicates that the absorption of light with energy larger than the materials band gap plays an important role and points towards the nonthermal mechanism of the photostimulated solid state reaction. [ABSTRACT FROM AUTHOR]

The nature of internal mechanical stresses in the thin silicon-on-sapphire (SOS) epitaxial films is studied, and their value is estimated. They are ∼1019 Pa and have a compressive character. The effects of pulsed laser and lamp annealings on stress relaxation are analyzed, and stress relaxation is shown to reach 90% under certain annealing conditions. An electron mechanism, which is based on a change in the quantum state of the electron subsystem of a crystal during pulsed photon annealing, is proposed for annealing of structural defects. [ABSTRACT FROM AUTHOR]

Laser annealing of amorphous silicon (a-Si) at different initial temperatures (77 and 300 K) has been studied. It is established that the laser-stimulated crystallization of silicon is possible at relatively low temperatures. A theoretical model is proposed, which explains this phenomenon by melting via the electron mechanism followed by recrystallization. [ABSTRACT FROM AUTHOR]

We have studied the effect of neutron irradiation on the microhardness of n-GaAs crystals. It is shown that the growth and saturation of microhardness with increasing radiation dose Φ, as previously reported in the literature, take place only in the dose range Φ ∼ 1015-5×1016 cm-2. As the neutron dose is increased further, the microhardness continues to grow due to the increasing role of the radiation-induced disordered regions in n-GaAs. [ABSTRACT FROM AUTHOR]

We have studied the effect of neutron irradiation on the exciton absorption inn-GaAs crystals. It is shown that the observed decrease in the absorption coefficient, broadening of the exciton peak, and its shift toward higher energies are caused by the electric and strain (compression) fields generated by the radiation-induced defects. [ABSTRACT FROM AUTHOR]

A novel kind of synthesis for oxide materials, especially complex ones, has been developed. The process involves the intense irradiation of the powder mixture of the starting oxides by light at elevated temperature. The spectral range tested extends from infrared to ultraviolet with sufficient intensity for the solid-state reaction between the reagents to take place. The resulting reaction speed exceeds the conventional thermal one by up to two orders of magnitude. This method should be applicable for the synthesis of epitaxial thin films of high- TC superconductors used in RABITS or IBAD technologies, high-Q filters, and magnetic oxide films for magnetoelectronics. [ABSTRACT FROM AUTHOR]

Superconducting properties of YBa2Cu3O7-x (YBCO)/SrTiO3 (STO) polycrystalline composites were investigated. The composites were obtained by rapid thermal processing of the 20% YBCO–80% STO mixtures in the air in the temperature range 700–1000 °C for 2 min. Magnetization measurements showed that the superconducting critical temperature (Tc) is practically not changed if optimally doped YBCO is used in YBCO/STO composites. In contrast, a strong increase of Tc from 65 to 90 K was found in the case of underdoped YBCO. This increase of Tc can be explained by unusually fast diffusion of oxygen from STO to YBCO grains in sintered composites. Obtained results show that the YBCO oxidation process can be significantly accelerated in underdoped YBCO/STO composites during rapid high-temperature processing. [ABSTRACT FROM AUTHOR]