Nanodomain structures formation during polarization reversal in uniform electric field in strontium barium niobate single crystals

We have studied the ferroelectric nanodomain formation in single crystals of strontium barium niobate Sr 0.61Ba 0.39Nb 2O 6 using piezoelectric force microscopy and Raman confocal microscopy. The nanodomain structures have been created by application of the uniform electric field at room temperature. Four variants of nanodomain structure formation have been revealed: (1) discrete switching, (2) incomplete domain merging, (3) spontaneous backswitching, and (4) enlarging of nanodomain ensembles. Kinetics of the observed micro- and nanodomain structures has been explained on the basis of approach developed for lithium niobate and lithium tantalate crystals. © 2012 American Institute of Physics

Nanodomain structures formation during polarization reversal in uniform electric field in strontium barium niobate single crystals

We have studied the ferroelectric nanodomain formation in single crystals of strontium barium niobate Sr 0.61Ba 0.39Nb 2O 6 using piezoelectric force microscopy and Raman confocal microscopy. The nanodomain structures have been created by application of the uniform electric field at room temperature. Four variants of nanodomain structure formation have been revealed: (1) discrete switching, (2) incomplete domain merging, (3) spontaneous backswitching, and (4) enlarging of nanodomain ensembles. Kinetics of the observed micro- and nanodomain structures has been explained on the basis of approach developed for lithium niobate and lithium tantalate crystals. © 2012 American Institute of Physics

Investigation local switching and self-organization effects on non-polar cuts of lithium niobate

The equipment of the Ural Center for Shared Use “Modern Nanotechnology” Ural Federal University was used. The research was made possible by Russian Science Foundation (Grant 14-12-00826)

Oxide charge evolution under crystallization of amorphous Li–Nb–O films

Li–Nb–O amorphous films were deposited onto Si substrates by the radio-frequency magnetron sputtering method in an Ar environment and an Ar(60%)+O2(40%) gas mixture. A positive effective fixed oxide charge Qeff having negative, -Qeff, and positive, +Qeff, components, exists in the as-grown heterostructures. -Qeff is located near the substrate/film interface, whereas + Qeff is determined by a deficit of Li and O (vacancies) in the bulk of Li–Nb–O films. As-grown films crystallized under thermal annealing (TA) at temperatures up to 600 °C and revealed the formation of polycrystalline LiNbO3. TA at about 520 °C resulted in the formation of the second phase LiNb3O8, increasing + Qeff, and compensating -Qeff entirely. The dielectric constants of the as-grown films exhibit two peaks at the annealing temperatures of 450 °C and 550 °C, which are attributed to the total crystallization and recrystallization of the LN films under TA, respectively. © 2020 The AuthorsRussian Foundation for Basic Research, RFBR: 18-29-11062, 18-32-00959This research was supported by the Russian Foundation for Basic Research (Grant № 18-29-11062 and Grant № 18-32-00959 ). The equipment of the Ural Center for Shared Use “Modern Nanotechnology” of the Ural Federal University was used

Tip-induced domain growth on the non-polar cuts of lithium niobate single-crystals

Currently, ferroelectric materials with designed domain structures are considered as a perspective material for new generation of photonic, data storage, and data processing devices. Application of external electric field is the most convenient way of the domain structure formation. Lots of papers are devoted to the investigation of domain kinetics on polar surface of crystals while the forward growth remains one of the most mysterious stages due to lack of experimental methods allowing to study it. Here, we performed tip-induced polarization reversal on X- and Y-non-polar cuts in single-crystal of congruent lithium niobate which allows us to study the forward growth with high spatial resolution. The revealed difference in the shape and length of domains induced on X- and Y-cuts is beyond previously developed theoretical approaches used for the theoretical consideration of the domains growth at non-polar ferroelectric surfaces. To explain experimental results, we used kinetic approach with anisotropy of screening efficiency along different crystallographic directions. © 2015 AIP Publishing LLC

Characterization of LiMn2O4 cathodes by electrochemical strain microscopy

Electrochemical strain microscopy (ESM) is a scanning probe microscopy (SPM) method in which the local electrodiffusion is probed via application of AC voltage to the SPM tip and registration of resulting electrochemical strain. Here, we implemented ESM to measure local strain in bulk LiMn2O4 cathodes of a commercial Li-battery in different states of charge to investigate distribution of Li-ion mobility and concentration. Ramped AC ESM imaging and voltage spectroscopy were used to find the most reliable regime of measurements allowing separating and diminishing different contributions to ESM. This is not a trivial task due to complex geometry of the sample and various obstacles resulting in less predictable contributions of different origins into ESM response: electrostatic tip surface interactions, charge injection, electrostriction, and flexoelectricity. Understanding and control of these contributions is an important step towards quantitative interpretation of ESM data

Effect of reactive gas environment on domain structure and local switching of LiNbO3 thin films deposited on Si(001) by radio-frequency magnetron sputtering

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) and by Russian Foundation for Basic Research (Grant 18-32-00959)