Abstract: Modern Electronic Materials 7(4): 141-149 DOI : 10.3897/j.moem.7.4.80758 Authors : Nikolay A. Kalanda, Marta V. Yarmolich, Alexander L. Gurskii, Alexander V. Petrov, Aliaksandr L. Zhaludkevich, Oleg V. Ignatenko, Maria Serdechnova : In this work, solid solutions of La0.7Sr0.3Mn0.95Fe0.05O3-δ with different oxygen content were obtained by the solid-phase reactions technique. Based on the investigation of the dynamics of changes in the oxygen index (3 – δ) during heating of the samples, the formation of a stressed state in their grains as a result of annealing was established. This results in a decrease in the mobility of oxygen vacancies during the reduction of cations according to the Mn4+ + e– → Mn3+ scheme and explains the decrease of released oxygen amount with an increase of δ as well as the heating rate of the samples. When studying the magnetic properties of the obtained samples, it was found that the temperature dependence of the magnetization obeys the Curie–Weiss law and as the oxygen defficiency increases, the Curie temperature for solid solutions decreases. It was found that the particles are in a frozen ferromagnetic state when measured in the low-temperature region of the М (Т) dependence in “zero-field mode” at Т ˂ ТВ. The presence of ferromagnetism at Т ˃ ТВ leads to a magnetically ordered state, in which the resulting magnetic moment of the magnetic particle is influenced by thermal fluctuations. When considering the temperature values of the magnetization of lanthanum-strontium manganite samples, it was found that with an increase of temperature in the low-temperature region, magnetic ordering is disturbed due to the excitation of magnons with a quadratic dependence of the energy from the wave vector, the number of which increases in proportion to T3/2. This results in a decrease in the manganite magnetization. The observed temperature dependence of the magnetization measured in the “field-cooling mode” was approximated taking into account the quadratic and non-quadratic dispersion laws of the magnon spectrum. HTML XML PDF PubDate: Thu, 30 Dec 2021 18:01:48 +020
Abstract: Modern Electronic Materials 7(4): 127-139 DOI : 10.3897/j.moem.7.4.78587 Authors : Andrei A. Kharchenko, Julia A. Fedotova, Valeryia Yu. Slabukho, Alexander K. Fedotov, Alexey V. Pashkevich, Ivan A Svito, Maxim V. Bushinsky : Black phosphorus (b-P) single crystals having the n-type electrical conductivity produced in a high pressure set-up (~1 GPa) with six diamond anvils at 800 °C for 12 h have been studied. The electrical conductivity σ(Т,В) and the Hall constant Rh(Т,В) have been analyzed within one-band and two-band models as functions of temperature in the 2 < Т < 300 K range and magnetic field in the 0 < В < 8 T range. Fitting of the experimental σ(Т,В) and Rh(Т,В) curves suggests the following key properties of the crystals: (1) intrinsic conductivity type, (2) approximately equal electron and hole concentrations and mobilities, (3) anisotropic behavior of electron and hole conductivities, concentrations and mobilities and (4) combination of negative and positive contributions to magnetoresistance (magnetoresistive effect, MR). In a zero magnetic field the anisotropy coefficient α = [σа (Т) – σс (Т)]/σс (Т) below 50–70 K is positive whereas above 220 K its sign changes to negative due to a specific combination of the temperature dependences of carrier concentration and mobility. It has been shown that the negative sign of relative MR (negative magnetoresistive effect) dominates at T < 25 K and B < 6 T and is presumably caused by the effects of strong localization resulting from structural disorder. The positive MR sign (positive magnetoresistive effect) is associated with the Lorentz mechanism of carrier movement and exhibits itself above 25 K in 6–8 T magnetic fields. HTML XML PDF PubDate: Thu, 30 Dec 2021 16:51:22 +020
Abstract: Modern Electronic Materials 7(4): 115-126 DOI : 10.3897/j.moem.7.4.81721 Authors : Arkady V. Naumov, Dmitry L. Orehov : The current condition and outlooks of the world semiconductor and polycrystalline silicon (poly-Si) markets have been analyzed. A long period of low PS prices which hindered the growth of investments into the industry has now changed for price recovery to an investment attractive level. Demand and offer balance for the period until 2024 and for the long term has been analyzed, and the main currently used PS processes have been reviewed. The current poly-Si market proficiency is expected to remain in the near and medium terms. However the “green turn” of the energy industry announced by all the governments, the development of local markets and the price recovery to an investment attractive level have promoted the development of new PS fab projects. Of special importance for Russia is the choice of Siemens trichlorosilane process parameters. A specific feature of the Russian market is the presence of several very important fields (solar energy, microelectronics, high-power electronics, photonics and fiber optics) which are small by international standards and equally face raw material shortage. It appears that Russia will greatly benefit from integral projects delivering solutions of multiple raw materials supply problems. HTML XML PDF PubDate: Thu, 30 Dec 2021 12:57:17 +020
Abstract: Modern Electronic Materials 7(4): 167-175 DOI : 10.3897/j.moem.7.4.78569 Authors : Andrey S. Shportenko, Alexander M. Kislyuk, Andrei V. Turutin, Ilya V. Kubasov, Mikhail D. Malinkovich, Yuri N. Parkhomenko : Lithium niobate is a ferroelectric material finding a wide range of applications in optical and acoustic engineering. Annealing of lithium niobate crystals in an oxygen-free environment leads to appearance of black coloration and concomitant increasing electrical conductivity due to chemical reduction. There are plenty of literary data on the electrophysical properties of reduced lithium niobate crystals though contact phenomena occurring during electrical conductivity measurement as well as issues of interaction between the electrode material and the test specimens are almost disregarded. The effect of chromium and indium tin oxide electrodes on the results of measurements of electrophysical parameters at room temperature for lithium niobate specimens reduced at 1100 °C has been investigated. It was found that significant nonlinearities in the VACs of the specimens at below 5 V distort the specific resistivity readings for lithium niobate. This requires measurements at higher voltages. Impedance spectroscopy studies have shown that the measurement results are largely affected by capacities including those probably induced near the contacts. It has been shown that the experimental results are described adequately well by a model implying the presence of near-contact capacities that are parallel to the specimen’s own capacity. Possible mechanism of the induction of these capacities has been described and a hypothesis has been proposed of the high density of electron states at the electrode/specimen interface that can trap carriers, the concentration of trapped carriers growing with an increase in annealing duration. HTML XML PDF PubDate: Thu, 30 Dec 2021 12:33:49 +020
Abstract: Modern Electronic Materials 7(4): 151-165 DOI : 10.3897/j.moem.7.4.51073 Authors : Vladimir S. Berdnikov : This work is a brief overview of numerical study results for hydrodynamics and convective heat exchange for the classic Czochralski technique obtained at the Institute of Thermophysics, Siberian Branch of the Russian Academy of Sciences. Flow structure evolution has been compared for melts with Prandtl numbers Pr = 0.05, 16, 50 and 2700. The regularities of local and integral convective heat exchange in the crucible/melt/crystal system for thermal gravity, thermocapillary and heat-induced gravity capillary convection have been studied. The calculations have been carried out using the finite and compact difference methods. This work is a continuation of an article: Berdnikov VS (2019) Hydrodynamics and heat exchange of crystal pulling from melts. Part I: Experimental studies of free convection mode. Modern Electronic Materials 5(3): 91–100. https://doi.org/10.3897/j.moem.5.3.46647 HTML XML PDF PubDate: Thu, 30 Dec 2021 10:08:36 +020
Abstract: Modern Electronic Materials 7(3): 85-90 DOI : 10.3897/j.moem.7.3.75786 Authors : Gunnar Suchaneck : Magnetization is a key property of magnetic materials. Nevertheless, a satisfactory, analytical description of the temperature dependence of magnetization in double perovskites such as strontium ferromolybdate is still missing. In this work, we develop, for the very first time, a model of the magnetization of nanosized, magnetically inhomogeneous Sr2FeMoO6-δ nanoparticles. The temperature dependence of magnetization was approximated by an equation consisting of a Bloch-law spin wave term, a higher order spin wave correction, both taking into account the temperature dependence of the spin-wave stiffness, and a superparamagnetic term including the Langevin function. In the limit of pure ferromagnetic behavior, the model is applicable also to SFMO ceramics. In the vicinity of the Curie temperature (T/TC> 0.85), the model fails. HTML XML PDF PubDate: Thu, 30 Sep 2021 21:58:39 +030
Abstract: Modern Electronic Materials 7(3): 109-113 DOI : 10.3897/j.moem.7.3.74274 Authors : Kirill Brekhov, Sergey Lavrov, Andrey Kudryavtsev, Nikita Ilyin : Quasi-2D layers of transition metal dichalcogenides are promising candidates for creating saturable absorbers for pulsed lasers. However, the peculiarities of intense electromagnetic radiation’s influence on such structures have not been thoroughly studied. This paper explores the dynamics of photoexcited carriers in WSe2 flakes through experimental studies. These studies found that WSe2 flakes significantly change their optical properties under the influence of a high-power optical pump, allowed estimating the thermalization time of these structures (about 2 ps), and found that full relaxation takes more than 10 ps. The concentration of carriers in the semiconductor surface layer was estimated to be about 1028 m–3. It was found that standard description models of the optical response based on exciton resonances and absorption by free carriers could not adequately describe the experiments’ results. Thus, for an accurate description of the optical response, it was necessary to consider the effects associated with Coulomb screening that are caused by the high concentration of photo-excited carriers of the optical pumping densities used in this experiment. HTML XML PDF PubDate: Thu, 30 Sep 2021 17:45:05 +030
Abstract: Modern Electronic Materials 7(3): 99-108 DOI : 10.3897/j.moem.7.3.77105 Authors : Dmitriy G. Muratov, Lev V. Kozhitov, Egor V. Yakushko, Andrey A. Vasilev, Alena V. Popkova, Vitaly A. Tarala, Evgeniy Yu. Korovin : Magnetic nanoparticles play an important role in rapidly developing advanced branches of science and industry, e.g. fabrication of magnetic storage media, synthesis of ferromagnetic liquids, medicine and chemistry. One problem faced in the usage of magnetic nanoparticles is their high chemical activity leading to oxidation in air and agglomeration. The chemical activity of magnetic nanoparticles stems from the contribution of their large specific surface to volume ratio. Carbon coating of nanoparticles reduces the interaction between nanoparticles. FeCoAl/C metal-carbon nanocomposites have been synthesized using IR pyrolysis of polymer/metal salt precursors. The effect of synthesis temperature (IR heating) in the range from 500 to 700 °C on the structure and composition of the nanomaterials has been studied. We show that the forming particles are the FeCoAl ternary solid solution with a FeCo based bcc lattice. An increase in the synthesis temperature from 500 to 700 °C leads to an increase in the coherent scattering region of three-component nanoparticles from 5 to 19 nm. An increase in the aluminum content from 20 to 30% relative to Fe and Co results in an increase in the size of the nanoparticles to 15 nm but this also entails the formation of a Co based solid solution having an fcc lattice. An increase in the nanocomposite synthesis temperature and a growth of the relative Al content as a result of a more complete carbonization and the structure-building effect of metals reduce the degree of amorphousness of the nanocomposite carbon matrix and lead to the formation of graphite-like phase crystallites having an ordered structure. The effect of synthesis temperature and relative content of metals on the electromagnetic properties (complex permittivity and permeability) of the synthesized nanocomposites has been studied. Synthesis conditions affect the radio absorption properties of the nanocomposites, e.g. reflection loss (RL) in the 3–13 GHz range. HTML XML PDF PubDate: Thu, 30 Sep 2021 14:05:52 +030
Abstract: Modern Electronic Materials 7(3): 91-97 DOI : 10.3897/j.moem.7.3.76277 Authors : Julia A. Fedotova : Granular films containing Fe50Co50Zr10 alloy nanoparticles inside Pb0,81Sr0,04(Na0,5Bi0,5)0,15(Zr0,575Ti0,425)O3 (PZT) ferroelectric matrix possess a combination of functional magnetic and electrical properties which can be efficiently controlled by means of external electric or magnetic fields. The formation of the required granular structure in PZT matrix is only possible if synthesis is carried out in an oxygen-containing atmosphere leading to substantial oxidation of metallic nanoparticles. Thus an important task is to study the oxidation degree of metallic nanoparticles depending on synthesis conditions and the effect of forming phases on the electrical properties of the films. The relationship between the structural and phase state and electrical properties of granular FeCoZr)x (PZT)100-x films (30 ≤ x ≤ 85 at.%) synthesized in an oxygen-containing atmosphere at the oxygen pressure PO in a range of (2.4–5.0) · 10–3 Pa has been studied using X-ray diffraction, EXAFS and four-probe electrical resistivity measurement. Integrated comparative analysis of the structural and phase composition and local atomic order in (FeCoZr)x (PZT)100-x films has for the first time shown the fundamental role of oxygen pressure PO during synthesis on nanoparticle oxidation and phase composition. We show that the oxygen pressure being within PO = 3.2 · 10–3 Pa an increase in x leads to a transition from nanoparticles of Fe(Co,Zr)O complex oxides to a superposition of complex oxides and a-FeCo(Zr,O) ferromagnetic nanoparticles (or their agglomerations). At higher oxygen pressures РО = 5.0 · 10–3 Pa the nanoparticles undergo complete oxidation with the formation of the (FexCo1-x)1-δO complex oxide having a Wurtzite structure. The forming structural and phase composition allows one to explain the observed temperature dependences of the electrical resistivity of granular films. These dependences are distinguished by a negative temperature coefficient of electrical resistivity over the whole range of film compositions at a high oxygen pressure (РО = 5.0 · 10–3 Pa) and a transition to a positive temperature coefficient of electrical resistivity at a lower oxygen pressure (РО = 3.2 · 10–3 Pa) in the synthesis atmosphere and x> 69 at.% in the films. The transition from a negative to a positive temperature coefficient of electrical resistivity which suggests the presence of a metallic contribution to the conductivity is in full agreement with the X-ray diffraction and EXAFS data indicating the persistence of unoxidized a-FeCo(Zr,O) ferromagnetic nanoparticles or their agglomerations. HTML XML PDF PubDate: Thu, 30 Sep 2021 13:53:12 +030
Abstract: Modern Electronic Materials 7(3): 79-84 DOI : 10.3897/j.moem.7.3.76700 Authors : Tatyana G. Yugova, Aleksandr G. Belov, Vladimir E. Kanevskii, Evgeniya I. Kladova, Stanislav N. Knyazev, Irina B. Parfent'eva : A theoretical model has been developed for determining the free electron concentration in n-InAs specimens from characteristic points in far IR reflection spectra. We show that this determination requires plasmon-phonon coupling be taken into account, otherwise the measured electron concentration proves to be overestimated. A correlation between the electron concentration Nopt and the characteristic wavenumber ν+ has been calculated and proves to be well fit by a third order polynomial. The test specimens have been obtained by tin or sulfur doping of indium arsenide. The electron concentration in the specimens has been measured at room temperature using two methods: the optical method developed by the Authors (Nopt) and the conventional four-probe Hall method (the Van der Pau method, NHall). The reflecting surfaces of the specimens have been chemically polished or fine abrasive ground. The condition Nopt> NHall has been shown to hold for all the test specimens. The difference between the optical and the Hall electron concentrations is greater for specimens having polished reflecting surfaces. The experimental data have been compared with earlier data for n-GaAs. A qualitative model explaining the experimental data has been suggested. HTML XML PDF PubDate: Thu, 30 Sep 2021 10:53:30 +030
Abstract: Modern Electronic Materials 7(2): 33-43 DOI : 10.3897/j.moem.7.2.65572 Authors : Vladimir N. Jarkin, Oleg A. Kisarin, Tatyana V. Kritskaya : Novel technical solutions and ideas for increasing the yield of solar and semiconductor grade polycrystalline silicon processes have been analyzed. The predominant polycrystalline silicon technology is currently still the Siemens process including the conversion of technical grade silicon (synthesized by carbon-thermal reduction of quartzites) to trichlorosilane followed by rectification and hydrogen reduction. The cost of product silicon can be cut down by reducing the trichlorosilane synthesis costs through process and equipment improvement. Advantages, drawbacks and production cost reduction methods have been considered with respect to four common trichlorosilane synthesis processes: hydrogen chloride exposure of technical grade silicon (direct chlorination, DC), homogeneous hydration of tetrachlorosilane (conversion), tetrachlorosilane and hydrogen exposure of silicon (hydro chlorination silicon, HC), and catalyzed tetrachlorosilane and dichlorosilane reaction (redistribution of anti-disproportioning reaction). These processes remain in use and are permanently improved. Catalytic processes play an important role on silicon surface, and understanding their mechanisms can help find novel applications and obtain new results. It has been noted that indispensable components of various equipment and process designs are recycling steps and combined processes including active distillation. They provide for the most complete utilization of raw trichlorosilane, increase the process yield and cut down silicon cost. HTML XML PDF PubDate: Wed, 30 Jun 2021 18:22:42 +030
Abstract: Modern Electronic Materials 7(2): 73-78 DOI : 10.3897/j.moem.7.2.76286 Authors : Roman Yu. Kozlov, Svetlana S. Kormilitsina, Elena V. Molodtsova, Eugene O. Zhuravlev : Currently there is a worldwide trend to increase the diameter of crystals grown from elemental semiconductors and semiconductor compounds. According to literary data the diameter of 3–5 semiconductor single crystals grown nowadays is 4 to 6 inches. So far up to 75 mm indium antimonide single crystals have been grown in Russia. Indium antimonide is the element base for the widest field of solid state electronics, i.e., optoelectronics. Indium antimonide is used for the fabrication of 3–5 mm range linear photodetectors and photodetector arrays used as light-sensitive material in heat vision systems. Growth heat conditions have been selected and 100 mm [100] indium antimonide single crystals have been grown using the modified two-stage Czochralski technique. The graphite heating unit has been oversized to accommodate a 150 mm crucible and a 4.5–5 kg load. The results of the work have provided for a substantial increase in the yield of photodetectors. The electrophysical properties of the as-grown single crystals have been studied using the Van der Pau method and proved to be in agreement with the standard parameters of undoped indium antimonide. Using the 9-field etch method of pit counting under an optical microscope the dislocation density in the 100 mm single crystals has been measured to be ≤ 100 cm-2which is similar to that for 50 mm single crystals. HTML XML PDF PubDate: Wed, 30 Jun 2021 17:00:24 +030
Abstract: Modern Electronic Materials 7(2): 45-51 DOI : 10.3897/j.moem.7.2.73289 Authors : Andrey N. Aleshin, Nikolay V. Zenchenko, Oleg A. Ruban : The operation of the TiN/HfO2/Pt bipolar memristor has been simulated by the finite elements method using the Maxwell steady state equations as a mathematical basis. The simulation provided knowledge of the effect of conductive filament thickness on the shape of the I–V curve. The conductive filament has been considered as the highly conductive Hf ion enriched HfOx phase (x < 2) whose structure is similar to a Magneli phase. In this work a mechanism has been developed describing the formation, growth and dissolution of the HfOx phase in bipolar mode of memristor operation which provides for oxygen vacancy flux control. The conductive filament has a cylindrical shape with the radius varying within 5–10 nm. An increase in the thickness of the conductive filament leads to an increase in the area of the hysteresis loop of the I–V curve due to an increase in the energy output during memristor operation. A model has been developed which allows quantitative calculations and hence can be used for the design of bipolar memristors and assessment of memristor heat loss during operation. HTML XML PDF PubDate: Wed, 30 Jun 2021 15:29:41 +030
Abstract: Modern Electronic Materials 7(2): 53-61 DOI : 10.3897/j.moem.7.2.75519 Authors : Pavel V. Shalaev, Polina A. Monakhova, Sergey A. Tereshchenko : Five samples of liquid dispersions of colloidal gold nanorods having various aspect ratios have been studied using light scattering methods. Transmission electron microscopy has been employed as a reference method. Advantages and drawbacks of dynamic light scattering and nanoparticle tracking analysis methods for study of nanoparticle geometrical parameters and concentration, sample monodispersity degree and detection of large particle aggregations and quasispherical impurities have been demonstrated. We show that depolarized dynamic light scattering method can be used for analysis of geometrical parameters of colloidal gold nanorods in liquid dispersions. The measurement results depend largely on the presence of large impurity particles or particle aggregations in samples. In turn the presence of large particles in dispersions can be detected using dynamic light scattering methods or nanoparticle tracking analysis. Dynamic light scattering method is more sensitive to the presence of even small quantities of large impurities or aggregations in samples. The monodispersity degree of nanorod liquid dispersions can also be assessed using dynamic light scattering and nanoparticle tracking analysis methods, and the measurement results can be considered more statistically significant in comparison with electron microscopy because a larger number of particles are analyzed. An increase in the concentration of spherical particles in compound dispersions of colloidal gold nanospheres and nanorods leads to a decrease in the contribution of the rotational mode to the overall scattering intensity. Data on the concentration of quasispherical impurities in samples of colloidal gold nanorod liquid dispersions have been reported on the basis of scattered light depolarization degree measurements. HTML XML PDF PubDate: Wed, 30 Jun 2021 12:54:34 +030
Abstract: Modern Electronic Materials 7(2): 63-71 DOI : 10.3897/j.moem.7.2.73293 Authors : Kira L. Enisherlova, Lev A. Seidman, Ella M. Temper, Yuliy A. Kontsevoy : The effect of parameters of plasma enhanced chemical vapor deposition (PECVD) processes for SiNx film fabrication on the electrical parameters of dielectric/АlGaN/GaN structures has been studied. The effect of growing film composition, additional heterostructure surface treatment with nitrogen plasma before dielectric deposition and HF biasing during treatment on the parameters of the С–V and I–V curves of SiNx/АlGaN/GaN structures has been analyzed. We show that films with nitrogen to silicon concentration ratios of 60 and 40% and a high oxygen content exhibit a decrease in the positive fixed charge in the structures although the I–V curves of the structures exhibit current oscillations. Information has been reported on the effect of PECVD process mode on current oscillation parameters, e.g. period and amplitude, and length of I–V curve section in which oscillations occur. Possible explanation of these oscillations has been suggested. Additional nitrogen plasma treatment of heterostructure surface before monosilane supply to the chamber changes the magnitude and sign of fixed charge and reduces the free carrier concentration in the 2D gas channel of SiNx/АlGaN/GaN heterostructures. Experimental evidence has been provided for the effect of PECVD process parameters and surface preparation on the electrical parameters of the heterostructures grown. HTML XML PDF PubDate: Wed, 30 Jun 2021 10:31:33 +030
Abstract: Modern Electronic Materials 7(1): 1-10 DOI : 10.3897/j.moem.7.1.64953 Authors : Vladimir N. Jarkin, Oleg A. Kisarin, Tatyana V. Kritskaya : Novel technical solutions and ideas for increasing the yield of solar and semiconductor grade polycrystalline silicon processes have been analyzed. The predominant polycrystalline silicon technology is currently still the Siemens process including the conversion of technical grade silicon (synthesized by carbon-thermal reduction of quartzites) to trichlorosilane followed by rectification and hydrogen reduction. The cost of product silicon can be cut down by reducing the trichlorosilane synthesis costs through process and equipment improvement. Advantages, drawbacks and production cost reduction methods have been considered with respect to four common trichlorosilane synthesis processes: hydrogen chloride exposure of technical grade silicon (direct chlorination, DC), homogeneous hydration of tetrachlorosilane (conversion), tetrachlorosilane and hydrogen exposure of silicon (hydro chlorination silicon, HC), and catalyzed tetrachlorosilane and dichlorosilane reaction (redistribution of anti-disproportioning reaction). These processes remain in use and are permanently improved. Catalytic processes play an important role on silicon surface, and understanding their mechanisms can help find novel applications and obtain new results. It has been noted that indispensable components of various equipment and process designs are recycling steps and combined processes including active distillation. They provide for the most complete utilization of raw trichlorosilane, increase the process yield and cut down silicon cost. HTML XML PDF PubDate: Tue, 30 Mar 2021 13:52:56 +030
Abstract: Modern Electronic Materials 7(1): 11-16 DOI : 10.3897/j.moem.7.1.73283 Authors : Yulia S. Terekhova, Dmitry A. Kiselev, Alexander V. Solnyshkin : Ceramic and polymer based nanocomponents combine the properties of their constituents, e.g. flexibility, elasticity, polymer reprocessability, hardness typical of glass, wear resistance and high light refraction index. This helps improving many properties of the materials in comparison with the source components. Since recently researchers have been manifesting interest to the properties of complex composite compounds. This is primarily caused by the unique properties of their structures as compared with conventional materials having homogeneous composition. Secondly, this interest is caused by the fact that these compounds may prove to be much cheaper than homogeneous structures provided the physical properties of the composite in a preset range of parameters (temperature, applied field frequency etc.) are identical to those of the respective homogeneous materials. For example, polyvinyl idenfluoride (PVDF) type ferroelectric polymers and copolymers on its basis have found wide application for functional elements of various electromechanic devices in advanced electronics due to their relatively good piezoelectric and pyroelectric properties. The strong random polarization and the formation of polar non-centrosymmetric crystals provide for the high piezoelectric and pyroelectric activity in these crystals. Scanning probe microscopy has been used for study of ferroelectric nanocomposites having different compositions. The matrix specimen for study of local polarization switching at a nanoscale level was vinyl idenfluoride and trifluoroethylene P(VDF-TrFE) copolymer possessing sufficiently high crystallinity. The composite fillers were barium titanate BaTiO3 and deuterized triglycinsulfate DTGS ferroelectric powders and zirconate-titanate lead barium BPZT ceramic powder. We show these materials to show good promise for use in memory cells. HTML XML PDF PubDate: Tue, 30 Mar 2021 12:19:02 +030
Abstract: Modern Electronic Materials 7(1): 21-30 DOI : 10.3897/j.moem.7.1.65581 Authors : Izatullo N. Ganiev, Firdavs A. Aliev, Haydar O. Odinazoda, Ahror M. Safarov, Rakhmazhon Usmonov : The effect of impurities on the electrical conductivity of aluminum has been studied in detail. The electrical conductivity of aluminum is 65.45% of that of copper. The tensile strength of aluminum wire is 150–170 MPa which, at equal conductivity, is about 65% of the strength of copper wire. This strength of aluminum wire is sufficient for bearing the wire’s own weight but may be too low in case of snow, ice or wind overloads. One way to improve the strength of aluminum wire is to use aluminum alloys having higher strength combined with sufficiently high electrical conductivity, e.g. the E-AlMgSi alloy (Aldrey). The key strengthening agent of the E-AlMgSi alloy (Aldrey) is the Mg2Si phase which imparts high mechanical strength to aluminum. In this work we present experimental data on the kinetics of high-temperature oxidation and electrochemical corrosion of indium doped E-AlMgSi aluminum conductor alloy (Aldrey). Thermal gravimetric study has shown that indium doping and high temperature exposure increase the oxidation rate of E-AlMgSi alloy (Aldrey), with the apparent alloy oxidation activation energy decreasing from 120.5 to 91.8 kJ/mole. Alloy oxidation rate data determined using a potentiostatic technique in NaCl electrolyte media have shown that the corrosion resistance of the indium doped alloy is 20–30% superior to that of the initial alloy. With an increase in NaCl electrolyte concentration the electrochemical potentials of the alloys decrease whereas the corrosion rate increases regardless of alloy composition. HTML XML PDF PubDate: Tue, 30 Mar 2021 11:56:18 +030
Abstract: Modern Electronic Materials 7(1): 31-32 DOI : 10.3897/j.moem.7.1.73285 Authors : Pavel P. Fedorov : Review on the paper Wuzong Zhou, Reversed Crystal Growth. Crystals. 2019; 9(1): 7 (16 pp). https://doi.org/10.3390/cryst9010007 HTML XML PDF PubDate: Tue, 30 Mar 2021 11:40:29 +030
Abstract: Modern Electronic Materials 7(1): 17-20 DOI : 10.3897/j.moem.7.1.66773 Authors : Anatolii A. Mololkin, Dmitry V. Roshchupkin, Eugenii V. Emelin, Rashid R. Fahrtdinov : Lithium niobate and tantalate are among the most important and widely used materials of acoustooptics and acoustoelectronics. They have high piezoelectric constants enabling their use as actuators. Their use is however restricted by the thermal instability of lithium niobate crystals and the low Curie temperature TC of lithium tantalate crystals. Overcoming these drawbacks typical of some compounds is possible by growing LiNb1-xTaxO3 single crystals. Good quality LiNb1-xTaxO3 single crystals have been grown using the Czochralsky technique. High-temperature poling process of LiNb1-xTaxO3 single crystals has been studied. The main differences between the process modes required for poling of congruent LiNb1-xTaxO3 single crystals and congruent LiNbO3 single crystals have been demonstrated. Parameters of high-temperature electric diffusion processing of LiNb1-xTaxO3 single crystals that provide for singledomain crystals for further study of physical properties have been reported. HTML XML PDF PubDate: Tue, 30 Mar 2021 11:24:29 +030
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