Stick and slip states in the probe-sample force interaction and informative nanomechanical measurements using AFM

The work was supported by FTP № 14.604.21.0200 (RFMEFI60417X0200)

Study of charge state of polarization domain walls in organic ferroelectric 2-methylbenzimidazole crystals

The work is supported by the RFBR grant № 16-02-00399

AFM probe tip displacement calibrations along three orthogonal directions

Латеральные и нормальные калибровочные коэффициенты для определения движений кончика зонда атомно-силового микроскопа в плоскости образца и по нормали к ней исследованы аналитически, c использованием тензора обратной жесткости для прямоугольного кантилевера, а также экспериментально, на горизонтальной (100) и вертикальной (011) гранях монокристаллических шайб GaAs, и на наклонных гранях тестовой решетки TGG1. Расчеты нормальных коэффициентов хорошо согласуются с измерениями на разных типах популярных кантилеверов. Латеральные коэффициенты удовлетворительно согласовывались только для мягких контактных кантилеверов. Для согласования расчетов с экспериментальными калибровками жестких кантилеверов рассмотрены вклады жесткости зонда (смоделированного, например, усеченным конусом), а также контактной жесткости. В заключение вынесено обсуждение оптимальных вариантов кантилеверов для актуальных в последнее время измерений латеральных и нормальных сигналов пьезоотклика от сегнетоэлектрических образцов.Lateral and normal calibration coefficients determining the motion of the very end of the probe of the atomic force microscope are studied both theoretically and experimentally. First we analyze the inverse stiffness tensor data for a set of popular rectangular cantilevers, to calculate the coefficient values. We present the results of calibration measurements conducted on horizontal (100) and vertical (011) faces of GaAs crystal samples, as well as on the tilted faces of the test sample TGG1. Calculations and measurements agree well for normal calibration coefficients. Measured lateral calibration coefficients correspond to the calculated ones only for soft contact cantilevers. The contributions due to probe (modeled, for example, by a truncated cone) and sample deformations to the calculated coefficients are taken into account. This helps to explain the measured low lateral coefficients for noncontact cantilevers. To conclude, we discuss the optimal cantilever parameters to improve the sensitivity of lateral and normal signals in piezoresponse force microscopy of ferroelectric samples

Thermodynamics of rapid solidification and crystal growth kinetics in glass-forming alloys

Thermodynamic driving forces and growth rates in rapid solidification are analysed. Taking into account the relaxation time of the solute diffusion flux in the model equations, the present theory uses, in a first case, the deviation from local chemical equilibrium, and ergodicity breaking. The second case of ergodicity breaking may exist in crystal growth kinetics of rapidly solidifying glass-forming metals and alloys. In this case, a theoretical analysis of dendritic solidification is given for congruently melting alloys in which chemical segregation does not occur. Within this theory, a deviation from thermodynamic equilibrium is introduced for high undercoolings via gradient flow relaxation of the phase field. A comparison of the present derivations with previously verified theoretical predictions and experimental data is given. This article is part of the theme issue 'Heterogeneous materials: Metastable and nonergodic internal structures'. ©2019 The Author(s) Published by the Royal Society

Peculiarities of living cell response to external influences revealed via quasistatic mode atomic force microscopy

Атомно-силовая микроскопия в квазистатическом режиме PeakForce QNM была применена для изучения морфологии и модуля Юнга живых клеток. В физиологически адекватных условиях исследовались эритроциты, фибробласты, сенсорные нейроны.Quasistatic PeakForce QNM mode of atomic force microscopy has been employed to study the morphology and the Young's modulus of living cells. Erythrocytes, fibroblasts, sensory neurons were investigated under physiologically relevant conditions

Development of Recommendations for the Introduction of Megapolis Charging Stations for Electric Cars in the Transport Infrastructure

The article describes the state of the transport infrastructure of the metropolis on the example of the city of Yekaterinburg, and what steps need to be taken to promote electric vehicles in the Yekaterinburg city.Описывается состояние транспортной инфраструктуры мегаполиса на примере города Екатеринбурга, и какие шаги необходимо предпринять для популяризации электромобилей в г. Екатеринбург

Evidence for short range orbital order in paramagnetic insulating (Al,V)_2O_3

The local structure of (Al_0.06V_0.94)_2O_3 in the paramagnetic insulating (PI) and antiferromagnetically ordered insulating (AFI) phase has been investigated using hard and soft x-ray absorption techniques. It is shown that: 1) on a local scale, the symmetry of the vanadium sites in both the PI and the AFI phase is the same; and 2) the vanadium 3d - oxygen 2p hybridization, as gauged by the oxygen 1s absorption edge, is the same for both phases, but distinctly different from the paramagnetic metallic phase of pure V_2O_3. These findings can be understood in the context of a recently proposed model which relates the long range monoclinic distortion of the antiferromagnetically ordered state to orbital ordering, if orbital short range order in the PI phase is assumed. The measured anisotropy of the x-ray absorption spectra is discussed in relation to spin-polarized density functional calculations.Comment: 8 pages, 5 figure