arXiv subjects

V. M. Mukhortov

Publications and source records attributed to V. M. Mukhortov.

6 recordsLinked to original sources

arXiv2020

Light effect on the interface resistance of Ba$_{0.8}$Sr$_{0.2}$TiO$_3$/LaMnO$_3$ heterosctructure

The effect of green and ultraviolet laser light on Ba$_{0.8}$Sr$_{0.2}$TiO$_3$/LaMnO$_3$ heterostructure electrical resistance was studied. In 80-200 K range illumination induces transient resistance component at ~15% of the steady-state value, the time constant associated with the transient component is ~12 s. The negative photoresistance effect is found under green, infrared and ultraviolet illumination.

cond-mat.mes-hall↗

arXiv2019

Magnetic-field effect in the heterostructure Ba$_{0.8}$Sr$_{0.2}$TiO$_3$/LaMnO$_3$

We have studied transport and magnetotransport properties of the heterostructure consisting of the ferroelectric Ba$_{0.8}$Sr$_{0.2}$TiO$_3$ film deposited on the single crystalline manganite LaMnO$_3$. Two-dimensional electron gas arising at the interface transforms the interface region of the antiferromagnetic manganite to the ferromagnetic state with the reoriented magnetic moments. We obtained that the contribution of these ferromagnetic regions to the resistance of the heterostructure appears to be dependent on the external magnetic field applied perpendicularly to the interface (and parallel to {\it c}-axis of the ferromagnetic state of LaMnO$_3$). We believe that the decrease of the resistance of the studied heterostructure under the influence of the external magnetic field is caused by an appearance of the ferromagnetic order in the interface area. This leads to a relatively small resistance. In turn, the cycling of the applied magnetic field leads to the increase of the regions of the ferromagnetic order and, as a result, to decreasing scattering of the current carriers at the ferromagnetic disordering.

cond-mat.mes-hall↗

arXiv2017

Two-dimensional electron gas at the interface of the ferroelectric-antiferromagnetic heterostructure Ba_0.8Sr_0.2TiO_3/LaMnO_3

The temperature dependence of the electrical resistivity of the heterostructures consisting of single crystalline LaMnO$_3$ samples with different crystallographic orientations covered by the epitaxial ferroelectric Ba$_{0.8}$Sr$_{0.2}$TiO$_3$ film has been studied. Results obtained for the heterostructure have been compared with the electrical resistivity of the single crystalline LaMnO$_3$ without the film. It was found that for the samples with the films where the polarization axis is perpendicular to the crystal surface the electrical resistivity strongly decreases, and at the temperature below ~160 K undergoes the insulator-metal transition. Ab-initio calculations were also performed for the structural and electronic properties of the BaTiO$_3$/LaMnO$_3$ heterostructure. Transition to the 2D electron gas at the interface is shown.

cond-mat.str-el↗

arXiv2010

Electric-field-induced monoclinic phase in (Ba,Sr)TiO$_3$ thin film

We have studied electric-field-induced symmetry lowering in the tetragonal (001)-oriented heteroepitaxial (Ba$_{0.8}$Sr$_{0.2}$)TiO$_3$ thin film deposited on (001)MgO substrate. Polarized micro-Raman spectra were recorded from the film area in between two planar electrodes deposited on the film surface. Presence of \textit{c}-domains with polarization normal to the substrate was confirmed from polarized Raman study under zero field, while splitting and hardening of the \textit{E}(TO) soft mode and polarization changes in the Raman spectra suggest monoclinic symmetry under external electric field.

cond-mat.mtrl-sci↗

arXiv2010

Polarization of thin films of barium-strontium titanate under external electric field

The Landau theory of phase transitions of Ba0.8Sr0.2TiO3 thin film under external electric field applied in the planar geometry is developed. The interfacial van-der-Waals field Ez=1.1x10^8 V/m oriented normal to the film-substrate interface was introduced in to the model calculation to explain experimentally observed behavior of the polarization as a function of planar electric field. The Ez - misfit strain phase diagram of the film is constructed and discussed.

cond-mat.mtrl-sci↗

arXiv2010

High frequency polarization switching of a thin ferroelectric film

We consider both experimentally and analytically the transient oscillatory process that arises when a rapid change in voltage is applied to a $Ba_xSr_{1-x}TiO_3$ ferroelectric thin film deposited on an $Mg0$ substrate. High frequency ($\approx 10^{8} rad/s$) polarization oscillations are observed in the ferroelectric sample. These can be understood using a simple field-polarization model. In particular we obtain analytic expressions for the oscillation frequency and the decay time of the polarization fluctuation in terms of the material parameters. These estimations agree well with the experimental results.

cond-mat.mtrl-sci↗