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Oleg Utesov

Publications and source records attributed to Oleg Utesov.

2 recordsLinked to original sources

Metastable solitonic states in the strained itinerant helimagnet FeGe

The tensile strain is a promising tool for creation and manipulation of magnetic solitonic textures in the chiral helimagnets via tunable control of magnetic anisotropy and Dzyaloshinskii-Moriya interaction. Here, by using the in-situ resonant small-angle x-ray scattering we demonstrate that the skyrmion and chiral soliton lattices can be achieved as metastable states in FeGe lamella as distinct states or even simultaneously by combining the tensile strain and magnetic fields in various orientations with respect to the deformation. The small-angle scattering data are discussed in the frame of the analytical model which is sufficient to describe the experimental results for soliton lattice. By using the experimental results and analytical theory, unwinding of the metastable skyrmions in the perpendicular magnetic field as seen by small-angle scattering experiment was analyzed by the micromagnetic simulation.

cond-mat.mes-hall

Substrate-induced reduction of graphene thermal conductivity

We develop the theory of heat conductivity in supported graphene, accounting for coherent phonon scattering on disorder induced by an amorphous substrate. We derive spectra for in-plane and out-of-plane phonons in the framework of Green's function approach. The energetic parameters of the theory are obtained using the molecular dynamics simulations for graphene on SiO$_2$ substrate. The heat conductivity is calculated by the Boltzmann transport equation. We find that the interaction with the substrate drastically reduces the phonon lifetime and completely suppresses the contribution of ZA phonons to the heat conductivity. As a result, the total heat conductivity is reduced by several times, which matches with the tendency observed for available experimental data. The considered effect is important for managing thermal properties of the graphene-based electronic devices.

cond-mat.mes-hall