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Introduction. Due to the criterion of recoverability, the dot peen marking is widely used as a protective one for such products as, for example, fi rearms or locking and sealing devices. However, in forensics, the possibilities of establishing the commonality of origin of such markings and identifi cation of specifi c equipment have not been investigated. Theoretical analysis. To solve these expert problems, a proven approach was chosen, which consists in studying the constructive and technological properties of dot peen markers as objects of forensic research. Empirical analysis. In the real production cycle of serial sealing devices, markings were made on 20 Pinstamp TMP1700 markings installation. In total, more than 90 products of several model ranges were examined. The main attention was paid to the display of group features of the image program (template); display of individual signs of a particular installation and stability of feature display. Comparative analysis showed that in the marking traces there is a complex of stably displayed group and individual signs of the technological installation. Results. The study of the identifi ed complex of features allows you to establish the production origin of the dot peen marking, the software settings of the template and individualize a specifi c marking installation.

There is no consensus among researchers regarding how phase transitions occur in antiferroelectric (AFE) epitaxial heterostructures, in particular, in heterostructures based on model AFE lead zirconate. The questions about the number of phase transitions in such films and by what mechanism they occur remain controversial. This paper presents a look at the phase transition scenario in two types of epitaxial heterostructures: PbZrO 3 /Ba[La–Sn]O 3 /MgO (001) thin films with thicknesses from 25 to 1000 nm and PbZrO 3 /SrRuO 3 /SrTiO 3 (001) thin film 100 nm thick using the diffuse x-ray scattering in the grazing incidence setup. We register the characteristic butterfly-shaped diffuse scattering (DS) intensity distribution in the H K pseudocubic planes, which corresponds to the anisotropic ferroelectric soft mode. No incommensurate soft mode was observed in the cuts of reciprocal space parallel to the film surface by diffuse scattering. We reproduce the shape of DS distribution at different temperatures by the model based on the dielectric stiffness and the electric polarization correlation tensor in the cubic approximation. Such modeling allows not only to characterize the DS parameters from the challengingly low signal-to-background data set, but also to extract experimentally the sensitivity of the materials with respect to inhomogeneous polarization. While the observed temperature evolution of DS is consistent with the dielectric measurements, the correlation between the DS and the phase transition sequence observed by superstructure reflections is yet to be understood better. [ABSTRACT FROM AUTHOR]

This work studies a chaotic potential (CP) in the heterojunctions of III-nitrides, the CP caused by the electrostatic field of charged dislocations, under localization conditions of a two-dimensional electron gas in the near-contact region. Within the framework of the statistical analysis of a Poisson ensemble of linear defects, the amplitude and scale of the CP in the contact plane have been determined. The CP parameter dependence on the density of surface states and the concentration of dislocations at the mobility threshold of the two-dimensional electron gas was shown. The CP amplitude was established to exceed 100 meV in a wide range of changes in the system parameters, in the presence of electronic charge localization effects in the heterojunctions.

Applications of epitaxial antiferroelectrics face scientific challenges, such as limited understanding of degraded (in comparison to bulk) switching behavior and its relation to nanoscale structural organization. We report on an unusual structural response of PbZrO3/SrRuO3/SrTiO3 (001) heterostructures to precritical (lower than required for switching) electric fields. In situ x-ray diffraction shows a ferrielectric-like structure, which forms gradually upon increasing the applied field and makes up a heterophase state with the host antiferroelectric phase. The field-induced structure is similar to the antiferroelectric parent phase in the octahedral-tilt pattern, but differs from it in the lead-ion displacement pattern. The latter can be encoded as provided that the antiferroelectric structure is encoded as. We propose that the unusual commensurateness (as opposed to the more ubiquitous incommensuration in similar materials) between the modulation periods of host and guest phases can be explained by accounting for the energy of heterophase boundaries, which is important in dense nanostructures due to the high surface-to-bulk ratio of nanodomains. An analysis using the ab-initio-correlated, but empirical (parametrized) energy model suggests that the observed field-induced structure is likely to be selected in PbZrO3 instead of the others in the case when the above commensuration effect is at play. The results point to the mechanism leading to the smearing of polarization-field loops in such heterostructures and suggest a perspective for the controlled creation of delicate dipolar orderings for ferroic-based memory.

The paper analyzes the structural features of perovskite-like ABO3 type materials responsible for the formation of antiferroelectric phases. For this purpose, the descriptions of some single crystals have been compared using three models: the adapted Slater dipole model (I), the Cowley shell model (II) and the Born – Karman model supplemented with consideration dipole-dipole forces and parameterized basing on ab initio calculations by Ghosez (III). The parameters of model I were found at which qualitative agreement with the data on inelastic X-ray scattering obtained by experiments with lead hafnate was observed. An analysis of all the results led to the conclusion that model I and the Ghosez parameterization confirmed the hypothesis about the key role of the lateral component of the oxygen atoms’ polarizability over its axial component for the antiferroelectricity formation. However, model II data did not support this.

Antiferroelectric (AFE) materials are interesting due to recent discoveries of new prospective applications, although the mechanisms of the phase transitions that are at the heart of these applications remain incompletely understood. This work is devoted to the study of a single crystal of a model AFE, lead hafnate, by X‐ray diffraction with in situ application of an electric field to trigger the transition to a polar phase. Two consecutive experiments were carried out on a 35 µm thick plate with [110] surface normal orientation over a field range from 0 to 330 kV cm−1 and back. A sharp drop in the intensity of R‐ and Σ‐type reflections around 225 kV cm−1 was registered, with almost complete disappearance after 250 kV cm−1. This is compatible with a field‐induced phase transition from the AFE to the R3m polar phase, which was suggested earlier on the basis of non‐diffraction characterizations. X‐ray diffraction reveals that the AFE domains with displacements parallel to the field direction react much more smoothly to the field, gradually reducing the AFE order at very small fields instead of holding it almost constant up to the critical field value, which is naturally expected. This expectation is fulfilled for domains with other orientations, but only for the first switching cycle; in the second switching cycle the AFE order already shows a notable decrease at subcritical fields. It is suggested that these observations could be linked with the antiphase domain wall population being affected by the field, which is consistent with the observation of diffuse rods between the Γ and Σ points. Another remarkable observation is the much smoother recovery of the AFE phase compared with its sharp disappearance at the critical field. [ABSTRACT FROM AUTHOR]

In order to analyze the technique of laser annealing of titanium dioxide films on sapphire substrates and to optimize the film properties, a thermomechanical model of this technique has been considered. The model allowed us to monitor and vary the values of thermoelastic stresses in the film-substrate structures caused by changes of film annealing technological parameters such as the laser power, the film thickness, the pulse duration, the speed of laser emission, etc. The temperature field under the laser beam was simulated and then the stresses were analyzed using the thermomechanical finite element model. The simulation results showed an important role of the TiO2 film-to-substrate thickness ratio. The optimal combination of technological parameters was selected to prevent formation of cracks and other defects in the films.