Vol 43, No 12 (2016)

Thermal quenching of interconfigurational 5d-4f luminescence of Er³⁺ and Tm³⁺ ions in BaY₂F₈ crystals is studied in the temperature range of 330–790 K. The quenching temperatures are ~575 and ~550 K for Er³⁺ and Tm³⁺, respectively. It is shown that quenching of 5d-4f luminescence of Tm³⁺ ions is caused by thermally stimulated ionization of 5d electrons to the conduction band.

The role of the electric field during manipulations with diamond nanoparticles on a silicon substrate by a scanning probe microscope (SPM) tip is studied. It is found that the attractive force appearing in the contact between nanodiamond and an electrically charged tip is sufficient to detach and displace a chosen nanoparticle from initial to goal position under moderate mechanical stresses of the probe to nanoparticle. The problem of the control of the tip motion trajectory during manipulations is solved by visualizing the tip trace of the sample surface. The results obtained will be used for precision positioning of single-photon emitters based on luminescent nanodiamonds in microcavities.

Within the self-consistent Hartree–Fock approximation, the equilibrium weakly nonideal Bose gas with a delta-shaped interaction potential in the presence of the Bose–Einstein condensate is considered without using quasi-averages. On this basis, using the virial theorem and diagram techniques of the perturbation theory for the equilibrium system in a macroscopic volume, the equation of state providing the isothermal compressibility finiteness, including the Bose–Einstein condensate domain of existence, is obtained.

The effect of sintering aids of SiO₂, ZrO₂, B₂O₃, and MgO oxides on the optimum sintering temperature, ceramics grain growth, total volume of residual pores, and optical quality of obtained ceramics is studied. The best combinations of sintering aids are found; as a result, YAG:Nd (1 at%) samples of ceramics of high optical quality are obtained. An original method for characterizing laser properties of ceramics is developed. Comparative measurements of main laser characteristics of the obtained ceramics and ceramics of the Konoshima Chemical Corp. Ltd wellknown in the world practice, are performed.

Nanocrystalline (NC) diamond films are grown by chemical vapor deposition on various single crystal diamond faces. Under conditions of NC diamond growth, the growing filmmorphology is reduced to two planes: {100} and {111}. The {100} planes are smooth and homoepitaxial layerby-layer growth occurs on them, whereas the NC film formed by twin crystalliteswith sizes of several tens and hundreds nanometers grows on {111} planes. Nitrogen impurity sharply increases the diamond growth rate.