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We have studied a dense domain structure (DDS) appearing during polarization reversal in rhombohedral (111)-cut lead magnesium niobate-lead titanate single crystals. The complicated shape of the switching current was explained by means of non-uniform motion of the boundary between the DDS and c-domains using comparative analysis of the optical current and kinetic map. 2D-vector piezoresponse force microscopy revealed that DDS represented needle-like a-domains inside the a-domains with different vertical orientations of spontaneous polarization. © 2020 Author(s). ; The equipment of the Ural Center for Shared Use "Modern Nanotechnology" UrFU was used. This work has been supported in part by the Ministry of Science and Higher Education of the Russian Federation under Project No. 3.9534.2017/8.9, by the Government of the Russian Federation (Act 211, Agreement No. 02.180 A03.21.0006) and by RFBR (Grant No. 17-52-80116-BRICS_a). This work was supported by the NSFC projects (Grant No. 51761145024), Shaan Xi province Project (Nos. 2017 ktpt-21 and 2018TD-024), and the 111 Project under Grant No. B14040.

In this paper, the predictive power of diffracxtive magneto-optics concerning domain structure and reversal mechanisms in ordered arrays of magnetic elements is demonstrated. A simple theoretical model based on Fraunhoffer diffraction theory is used to predict the magnetisation reversal mechanisms in an array of magnetic elements. Different domain structures and simplified models (or educated guesses) of the associated reversal mechanisms produce marked differences in the spatial distributions of the magnetisation. These differences and the associated magnetisation distribution moments are experimentally accessible through conventional and diffractive magneto-optical Kerr effect measurements. The domain and magnetisation reversal predictions are corroborated with Magnetic Force Microscopy (MFM) measurements. ; The authors acknowledge the service from the MiNa Laboratory at IMN funded by Comunidad de Madrid (S2018/NMT-4291 TEC2SPACE), MINECO (CSIC13-4E-1794) and the European Union (FEDER, FSE).

We demonstrate the abilities of various SEM techniques for domain imaging in PMN-PT crystals with different compositions. It is shown that the imaging of the chemically etched relief is limited by its destructivity and potential contrast - by low resolution and contrast instability. The optimal parameters of the imaging by backscattered electron channelling allow obtaining the high-resolution domain imaging in PMN-PT crystals. The domain structure change as a result of the phase transition are imaged. The correlation between the images of the surface domain structure obtained by scanning electron microscopy and piezoresponse force microscopy is demonstrated. © 2018 Institute of Physics Publishing. All rights reserved. ; The equipment of the Ural Centre for Shared Use "Modern Nanotechnology" Ural Federal University has been used. The research was made possible by RFBR (grant 17-52-80116-BRICS_a) and state task of Ministry of education and science of the Russian Federation (No. 3.4993.2017/6.7). The work was partially supported by Government of the Russian Federation (Act 211, Agreement 02.A03.21.0006). ; et al.;NT-MDT Spectrum Instruments;Ostec-ArtTool Ltd.;Promenergolab LLC;Russian Foundation for Basic Research;Taylor and Francis Group

The evolution of the domain structure (DS) of cubic submicron- and micron-sized magnetite particles has been studied in detail during "cooling" of specimens from the Curie temperature Тс to room temperature Тr followed by their "reheating" to Тс in order to determine the degree of irreversibility of DS changes during heat treatment and their possible effects on the thermoremanent magnetization (TRM) properties. It is shown that typical magnetic configurations in particles up to 2 μm in size have flower or vortex shapes with one or two vortices. A model of the formation of thermoremanent magnetization (TRM) in submicron-sized pseudo-single-domain particles (PSD) is proposed based on an expansion of Neel's single-domain thermofluctuation model of TRM acquisition. According to the model, the equality of blocking and deblocking temperatures is retained for submicron PSD grains. Consequently, for this magnetic fraction, the Thellier laws of pTRM additivity and independence must also be valid.

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).

The domain structures of Na1/2Bi1/2TiO3-BaxTiO3 (NBT-x%BT) crystals for x = 0, 4.5, and 5.5 have been investigated by polarized light and piezoresponse force microscopies. The results show that BaTiO3 (i) refines the size of polar nanoregions and enhances their self-organization, and (ii) suppresses the formation of proper ferroelastic domains at high temperatures in the paraelectric state, and it rather favors the formation of improper ones that form below the ferroelectric Curie temperature and that elastically accommodate the ferroelectric ones. ; National Science Foundation (Materials World Network)_DMR-0806592 ; U.S. Department of Energy DE-FG02-07ER46480 ; National Science Foundation of China 50602047 ; Shanghai Municipal Government 08JC1420500 ; China Scholarship Council

We have studied the influence of initial domain structure on piezoelectric and dielectric properties of Sr 0.61 Ba 0.39 Nb 2 O 6 single crystals slightly doped with Ce and Ni. Initial domain structure was created by zero-field cooling, in-field cooling, and partial switching. The difference in the frequency dependences of macroscopic piezoelectric response and temperature dependences of dielectric permittivity for various initial domain structures was revealed. © 2018 Institute of Physics Publishing. All rights reserved. ; Equipment of the Ural Centre for Shared Use "Modern nanotechnology" Ural Federal University was used. The research was made possible by Russian Foundation of Basic Research (project № 16-02- 00821-а) and state task of Ministry of education and science of the Russian Federation (No. 3.4993.2017/6.7). The work was partially supported by Government of the Russian Federation (act 211, agreement 02.A03.21.0006). Part of this work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT Ref. UID /CTM /50011/2013), financed by national funds through the FCT/MEC and when appropriate co-financed by FEDER under the PT2020 Partnership Agreement. ; et al.;NT-MDT Spectrum Instruments;Ostec-ArtTool Ltd.;Promenergolab LLC;Russian Foundation for Basic Research;Taylor and Francis Group

The modulation of binding affinities and specificities by post-translational modifications located out from the binding pocket of the third PDZ domain of PSD-95 (PDZ3) has been reported recently. It is achieved through an intra-domain electrostatic network involving some charged residues in the β2–β3 loop (were a succinimide modification occurs), the α3 helix (an extra-structural element that links the PDZ3 domain with the following SH3 domain in PSD-95, and contains the phosphorylation target Tyr397), and the ligand peptide. Here, we have investigated the main structural and thermodynamic aspects that these structural elements and their related post-translational modifications display in the folding/misfolding pathway of PDZ3 by means of site-directed mutagenesis combined with calorimetry and spectroscopy. We have found that, although all the assayed mutations generate proteins more prone to aggregation than the wild-type PDZ3, those directly affecting the α3 helix, like the E401R substitution or the truncation of the whole α3 helix, increase the population of the DSC-detected intermediate state and the misfolding kinetics, by organizing the supramacromolecular structures at the expense of the two β-sheets present in the PDZ3 fold. However, those mutations affecting the β2–β3 loop, included into the prone-to-aggregation region composed by a single β-sheet comprising β2 to β4 chains, stabilize the trimeric intermediate previously shown in the wild-type PDZ3 and slow-down aggregation, also making it partly reversible. These results strongly suggest that the α3 helix protects to some extent the PDZ3 domain core from misfolding. This might well constitute the first example where an extra-element, intended to link the PDZ3 domain to the following SH3 in PSD-95 and in other members of the MAGUK family, not only regulates the binding abilities of this domain but it also protects PDZ3 from misfolding and aggregation. The influence of the post-translational modifications in this regulatory mechanism is also discussed. ; This research was supported by grants CVI-05915, from the Andalusian Regional Government; BIO2009-13261-C02 and BIO2012-39922-C02, from the Spanish Ministry of Science and Education and FEDER; PI13-01330 from Instituto de Salud Carlos III and SGR09-0761 from the Generalitat de Catalunya. J.M-C. received a postdoctoral contract from the Spanish Ministry of Science and Education. M.M-A. was supported by a PIF (UAB) fellowship.

Historically underwater explosions (UEs) have been investigated for their huge military relevance, but they remain an important issue also for civil marine applications. As an example, UEs can occur near or on oil-gas plants due to severe environmental conditions or human errors and this has substantial consequences for the production. Preliminary information about time scales of the phenomenon and knowledge about possible strategies on how to limit the consequences of its interaction with close-by structures is crucial to make the proper decisions. A numerical investigation would in general require a 3D compressible (at least) two-phase hydro-dynamic solver strongly coupled with a suitable model of the involved structure. Because the CPU-time requirements are still too high for reliable and feasible predictions, a Domain Decomposition (DD) strategy has been proposed by Colicchio et al. (2013) and Colicchio et al. (2014) and applied to a fully coupled fluid-structure analysis by Colicchio et al. (2015). Here, the DD is further extended as Dynamic DD (DDD) to overcome limits of applicability in time. The dynamic strategy proposed is not limited to UEs problems and to the two coupled solvers involved. When examining the UE interaction with a marine structure, like a surface ship, one can distinguish basically two stages: the first one, with important compressible effects and local fluid-structure interactions; the second one, with global consequences for the structure, possibly involving large deformations and damages as well as free-surface waves generation. The present research focuses on the first stage but the proposed DDD strategy can be adopted also for the second stage.