Synthesis of nanostructured yttrium with the use of cluster beams and investigation of the optical and electrical properties of yttrium hydride species

The preparation of new types of nanosystems based on metallic yttrium nanoparticles, which are difficult to produce by traditional methods due to the high melting temperature and the extremely high oxidizability of this metal, has been investigated. The materials are prepared on an original high-vacuum setup intended for the formation of metal nanoparticle beams by laser ablation. Yttrium nanoparticles are synthesized, and their chemical reactions with hydrogen are studied at room temperature. It is found that the reaction at low hydrogen pressures ($\sim$10$^{-3}$ Pa) leads to the formation of YH$_2$ dihydride particles with metal properties. An increase in the hydrogen pressure to $\sim$100 Pa results in the transformation of metal-like YH$_2$ nanoparticles into dielectric YH$_{3-x}$ ($x <$ 1) nanoparticles. It is revealed that the last reaction corresponding to the metal-dielectric phase transition is reversible with respect to the pressure of the hydrogen atmosphere.