Theoretical Investigation of Phase Transitions of Graphite and Cubic 3C Diamond Into Hexagonal 2H Diamond Under High Pressures

Possible techniques for experimentally obtaining hexagonal diamond are studied in the scope of the density functional theory method. It has been found that hexagonal diamond may be created as a result of structural transition at 61 68 GPa uniaxial compression from orthorhombic AB graphite and at 57 66GPa from hexagonal AA graphite. Also the formation of hexagonal diamond is shown to take place in case of very strong 300 380 GPa compression of cubic diamond. X ray and electron microscopic data on nanodiamonds from meteorite craters are analyzed for the presence of hexagonal diamond. The analysis shows that impact origin carbon materials do not contain pure cubic and hexagonal diamonds, and the layers of nascent crystals of diamond polytypes are randomly packe

Domain formation by ion beam in lithium niobate crystal with suppression of surface charging by electron and UV-flood guns

The equipment of the Ural Center for Shared Use “Modern nanotechnology” Ural Federal University was used. The research was made possible by the Russian Science Foundation (grant № 17-72-10152)

Micro-Raman imaging of ferroelectric domain structures in the bulk of PMN-PT single crystals

We demonstrate the application of confocal Raman microscopy (CRM) for nondestructive imaging of ferroelectric domains both at the surface and in the bulk of lead magnesium niobate-lead titanate (PMN-PT) ferroelectric single crystals. The studied model periodical domain structure was created at a [001] cut of tetragonal-phase PMN-PT crystal by the electron beam patterning technique. It was shown that the surface CRM domain image coincides in details with the image obtained by piezoresponse force microscopy. © 2019 by the authors. Licensee MDPI, Basel, Switzerland.The research was funded by Russian Foundation for Basic Research (grant 17-52-80116-BRICS_a), National Natural Science Foundation of China (grant 51761145024), Government of the Russian Federation (act 211, agreement 02.180 A03.21.0006), and Ministry of Science and Higher Education of the Russian Federation (state task No. 3.4993.2017/6.7)

Polarization reversal in lithium niobate with compositional gradients

The equipment of Ural Center for Shared Use “Modern Nanotechnology” Ural Federal University was used. The research was made possible by Russian Science Foundation (Project № 19-12-00210)

Charged domain walls in lithium tantalate with compositional gradients produced by partial VTE process

The morphology of a single charged domain wall, appeared under the action of composition gradients produced by partial VTE procedure by Cherenkov-type second harmonic generation microscopy, was observed in detail. The width of the charged domain wall was estimated as 70 μm. Non-through and through narrow domains, grown from the charged domain wall, were revealed. The maximum length of non-through domains with submicron diameter was about 100 μm. The growth of narrow domains from the charged domain wall was demonstrated and attributed to the action of pyroelectric field. The widening of domains occurred after achieving the polar surface. © Published under licence by IOP Publishing Ltd.Russian Science Foundation, RSF: 19-12-00210The equipment of Ural Centre for Shared Use “Modern Nanotechnology” Ural Federal University was used. The research was made possible by Russian Science Foundation (project № 19-12-00210)

Electron beam poling of [001]c-poled PMN-39PT single crystal

The equipment of the Ural Center for Shared Use “Modern Nanotechnology” UrFU has been used. The research was made possible in part by Government of the Russian Federation (Act 211, Agreement 02.180 A03.21.0006) and RFBR (grant 17-52-80116-BRICS_a)

Charged domain walls in lithium tantalate with compositional gradients produced by VTE process

The equipment of Ural Center for Shared Use “Modern Nanotechnology” Ural Federal University was used. The research was made possible by Russian Science Foundation (Project № 19-12-00210)

Shape change of metal oxide nanoparticles produced by laser ablation in liquid

The equipment of the Ural Center for Shared Use “Modern Nanotechnology” UrFU was used. The work was supported by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006)

Shapes change of PbO nanoparticles produced by laser ablation in liquid

Production of non-spherical crystalline nanoparticles by laser ablation in liquid has been demonstrated recently. Here we studied the shape variety of PbO nanoparticles prepared by laser ablation in deionized water and IPA. The key role of water in the formation of PbO non-spherical nanostructures was demonstrated. Only spherical nanoparticles have been obtained in isopropyl alcohol (IPA). PbO non-spherical nanostructures have been formed only in presence of water, which supports the growth mechanism by oxidation. Using mixture of IPA and water in various proportions and revealing the time and temperature dependences of non-spherical nanostructure morphology can be used for controlled growth of PbO non-spherical nanostructures. © Published under licence by IOP Publishing Ltd.Government Council on Grants, Russian FederationMinistry of Science and Higher Education of the Russian Federation: 3.4993.2017/6.7, 3.9534.2017/8.9The work has been supported in part by the Ministry of Science and Higher Education of the Russian Federation (projects 3.9534.2017/8.9 and 3.4993.2017/6.7) and by Government of the Russian Federation (act 211, agreement 02.A03.21.0006). The equipment of the Ural Centre for Shared Use “Modern Nanotechnology” Ural Federal University was used

Electron beam domain patterning in thin plates of magnesium doped lithium niobate

The electron beam domain patterning has been studied in the thin crystalline plates of MgO-doped lithium niobate covered by artificial dielectric layer. The creation of the through periodic domain structures with vertical domain walls and a period down to 2 μm was demon-strated in the thin plates.The equipment of the Ural Center for Shared Use “Modern nanotechnology” Ural Federal University was used. The research was made possible by the Russian Science Foundation (grant № 17-72-10152)