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Nowadays, the technical advances call for efficient electromagnetic interference (EMI) shielding of transparent devices which may be subject to data theft. We developed Cu–Ag and Ni–Ag meshes on flexible PET substrate for highly efficiency transparent EMI shielding coating. Cu–Ag and Ni–Ag meshes obtained with galvanic deposition of copper and nickel on thin Ag seed mesh which was made by cracked template method. Coefficients S11, S21 and shielding efficiency (SE) were measured for Cu–Ag and Ni–Ag meshes in X-band (8–12 GHz) and K-band (18–26.5 GHz). 90 s copper deposition increase SE from 23.2 to 43.7 dB at 8 GHz with a transparency of 82.2% and a sheet resistance of 0.25 Ω/sq. The achieved maximum SE was 47.6 dB for Cu–Ag mesh with 67.8% transparency and 41.1 dB for Ni–Ag mesh with 77.8% transparency. Cu–Ag and Ni–Ag meshes have high bending and long-term stability. Minimum bend radius is lower than 100 µm. This effect allows to produce different forms of transparent shielding objects, for example, origami method. Our coatings are the leading among all literary solutions in three-dimensional coordinates: of sheet resistance–optical transmittance–cost of produced.

Series of high-quality spherical poly(methyl methacrylate) particles with a polydispersity less than 5% are prepared by chain-growth emulsifier-free controlled radical emulsion polymerization of methyl methacrylate in water. The average diameters in the series varied from 237 nm to 447 nm. The physico-chemical properties of obtained submicrospheres can be varied to make them more stable and stronger by a modified classical synthesis technology whereby 4-10 vol.% of dispersion medium is replaced by acetone. 2D and 3D photonic crystal structures, opals, are prepared from poly(methyl methacrylate) submicrospheres. The crystal structure of the opals is studied by IR spectroscopy and scanning electron microscopy. According to the spectroscopic data, the poly(methyl methacrylate) particles contain significant amounts of water whose evaporation leads to the shrinkage of the spheres. The stereoregularity of the synthesized polymer is studied, the glass-transition temperatures of obtained samples are determined.

In the work, sedimentation-stable sols of indium (III) and tin (IV) hydroxides were obtained by the Anion Resin Exchange Precipitation, which consists of the exchange reaction between the OH ions of the anion exchange resin and the anions of metal-containing solutions. The synthesized hydrosols were used to obtain conducting films of indium (III) In2O3 oxide and indium oxide doped with Tin In2O3: Sn, with a surface resistance of 4 kOhm/sq, thicknesses of 200–500 nm and a transparency of more than 85 %. The modes of applying precursors to glass substrates by the modified spray method and centrifugation method are selected. Films were studied using XRD, SEM, optical microscopy and spectrophotometry

The single-walled carbon nanotube-based thin films with a thickness from 11 ± 3 to 157 ± 18 nm have been formed using vacuum filtration. The thermal conductivity of the thin films as a function of thickness and temperature up to 450 K has been studied by the 3ω technique. It has been found that, in the region of 49 nm, the supplied heat from a gold strip started propagating with the high efficiency to the thin film plane. The thermal conductivity of the thin films with a thickness of 49 ± 8 nm was measured using the 3ω technique for bulk samples. It has been found that the thermal conductivity of the single-walled carbon nanotube-based thin films strongly depends on their thickness and temperature. The thermal conductivity sharply (by a factor of ~60) increases with an increase in thickness from 11 ± 3 to 65 ± 4 nm. In addition, it has been observed that the thermal conductivity of the thin film with a thickness of 157 ± 18 nm rapidly decreases from 211 ± 11 to 27.5 ± 1.4 W m–1 K–1 at 300 and 450 K, respectively.

Aluminum-doped zinc oxide thin films have been grown by atomic layer deposition at a temperature of 200°C. Using X-ray diffraction, it has been established that the ZnO:Al thin films exhibits the reflections from the (100), (002), (110), and (201) ZnO hexagonal phase planes. The (101) and (102) planes have also been detected by electron diffraction. The ZnO:Al thin films grow smooth with a root-mean-square roughness of Rq = 0.33 nm and characteristic nanocrystallite sizes of ~70 and ~15 nm without additional aluminum or aluminum oxide phases. The transmission at a wavelength of 550 nm with regard to the substrate has been found to be 96%. The refractive indices and absorption coefficients of the ZnO:Al thin films in the wavelength range of 250–900 nm have been determined. The maximum refractive indices and absorption coefficients have been found to be 2.09 at a wavelength of 335 nm and 0.39 at a wavelength of 295 nm, respectively. The optical band gap is 3.56 eV. The resistivity, Seebeck coefficient, and power factor of the ZnO:Al thin films are ∼1.02 × 10–3 Ω cm, –60 μV/K, and 340 μW m–1 K–2 at room temperature, respectively. The maximum power factor attains 620 μW m–1 K–2 at a temperature of 200°C.

This Letter presents the results of a study of the physical properties of micromesh transparent electrodes on a flexible substrate, obtained using a template in the form of silica layers subjected to controlled cracking. For the first time, a combined approach to the control of parameters of a micromesh structure (crack width and cell size) by varying the pH and the thickness of the sol layer is proposed. Using this approach, transparent electrodes with a surface resistance of 4.1 Ω/sq with a transparency of 85.7% were obtained. Micromesh electrodes are characterized by linear optical transmission in the visible and IR ranges, which opens up prospects for their use in optoelectronics.

Thin films have been produced via a spray method from commercially available single-walled carbon nanotubes (SWCNTs). A SWCNT film thickness has ranged from ~10 to ~80 nm. The SWCNT diameter has accepted values of 1.6–1.8 nm. The existence of SWCNTs longer than 10 μm is established. The optimal thickness of a SWCNT thin film is found to be ~15 nm at which the transmittance exceeds 85%. The specific resistance of SWCNT thin films goes from ~1.5 × 10–3 to ~3 × 10–3 Ohm cm at room temperature. The pioneering study of the temperature dependences of the Seebeck coefficient and surface resistance is performed for this type of SWCNT. A surface resistance is found to increase with rising temperature. Furthermore, the Seebeck coefficient of SWCNT thin films weakly depends on temperature. Its value for all samples is evaluated to be ~40 μV/K. According to the sign of the Seebeck coefficient, thin films exhibit hole-type conductivity. Moreover, the power factor of a 15-nm thin SWCNT-film decreases with a temperature increase to 140◦C from the value of approximately ~120 to ~60 μW m–1 K–2. A further rise in temperature has led to a gain in the power factor.

The results of structural and magnetic investigations of nanogranular Co–Al2O3 films formed from Co3O4/Al thin-film layered structures upon vacuum annealing are reported. The Co3O4/Al films have been obtained by sequential reactive magnetron sputtering of a metallic cobalt target in a medium consisting of the Ar + O2 gas mixture and magnetron sputtering of an aluminum target in the pure argon atmosphere. It is shown that such a technique makes it possible to obtain nanogranular Co–Al2O3 single- and multilayer thin films with a well-controlled size of magnetic grains and their distribution over the film thickness.

PMMA opal crystal was prepared by a simple hybrid method, which includes sedimentation, meniscus formation and evaporation. We investigated three surfaces of this crystal by angle-resolved reflective light spectroscopy and SEM study. The angle-resolved reflective measurements were carried out in the 400–1100 nm range. We have determined the high-quality ordered surface of the crystal region. Narrow particle size distribution of the surface has been revealed. The average particle diameter obtained with SEM was nearly 361 nm. The most interesting result was that reflectivity of the surface turned out up to 98% at normal light incidence. Using a fit of dependences of the maximum reflectivity wavelength from an angle based on the Bragg–Snell law, the wavelength of maximum 0° reflectivity, the particle diameter and the fill factor have been determined. For the best surface maximum reflectivity wavelength of a 0° angle was estimated to be 869 nm. The particle diameter and fill factor were calculated as 372 nm and 0.8715, respectively. The diameter obtained by fitting is in excellent agreement with the particle diameter obtained with SEM. The reflectivity maximum is assumed to increase significantly when increasing the fill factor. We believe that using our simple approach to manufacture PMMA opal crystals will significantly increase the fabrication of high-quality photonic crystal templates and thin films.

We have synthesized ferromagnetic nanocomposite Co-Al 2 O 3 thin films via a thermite reaction between Al and Co 3 O 4 with layer geometry. The starting Al/Co 3 O 4 bilayers were obtained by the deposition of Al layers onto Co 3 O 4 films at room temperature and were annealed at temperatures between 50 and 700 °C at 50 °C intervals. Above ∼450 °C the Co 3 O 4 partially transformed into the CoO phase. The simultaneous solid-state reactions of Al with Co 3 O 4 and Al with CoO started above the initiation temperature T in ∼500 °C, which did not depend on the bilayer thickness. After annealing at 700 °C about 60% of the Co was reduced by the Al and the rest of the Co was contained in intermediate CoAl 2 O 4 shells, which separated the Co nanoparticles from the Al 2 O 3 matrix. Above 700 °C the reaction was complete and the final products were noninteracting Co nanoparticles with an average size of ∼40 nm enveloped by CoAl 2 O 4 shells, which embedded into a dielectric Al 2 O 3 matrix. The synthesized Co-Al 2 O 3 nanocomposite films possessed soft magnetic behavior and good chemical stability.

Flexible film broadband absorber based on diamond-graphite mixture and polyethylene was fabricated by hot pressing. The film thickness of the absorber was 90 μm. We have measured angular reflectivity, diffusional reflectivity and transmittance in the range 85–8000 cm −1 (117–1.25 μm) in order to determine the absorption. It was shown that room temperature pressing of mesh print with 250 μm step significantly reduces reflectivity of the absorber. The absorption was over 0.85 in the range 85–320 cm −1 (117–31.25 μm) and >0.98 in the range 320–8000 cm −1 (31.25–1.25 μm). We believe that the designed and manufactured absorber might become a promising material for optical devices where high broadband absorption and flexibility are required.

The preparation of composite transparent electrodes of poly(3, 4-ethylenedioxythiophene) polystyrene sulfonate/single-wall carbon nanotubes by the spray method is described. The influence of the successive treatment of each functional layer in acid media with different activities on the optical and electric film characteristics is considered. The composite with the surface resistance of 89 Ω/sq at the transparency of 85.3% (550 nm) on a polymer substrate is obtained.

Co–ZrO 2 ferromagnetic nanocomposite thin films were successfully synthesized using a new thermite reaction between Zr and Co 3 O 4 in layer geometry. The initial Zr/Co 3 O 4 bilayers were obtained by the deposition of Zr layers onto Co 3 O 4 films at room temperature. The process of mixing at the Zr/Co 3 O 4 interface and synthesis of fine-crystalline Co and amorphous ZrO 2 phases started at a temperature above the initiation temperature T in ∼250 °С which did not depend on the bilayer thickness. For the bilayer thickness more than 300 nm high-temperature fcc-Co and cubic c-ZrO 2 (or tetragonal t-ZrO 2 ) phases were formed. For the bilayer thickness less than ∼50 nm stable low-temperature hexagonal hcp-Co and monoclinic m-ZrO 2 phases were also present in the reaction product. A partial transformation from Co 3 O 4 to CoO occurred after annealing at 300 °С. The secondary reaction between CoO and Zr started soon after Co 3 O 4 had been converted to the CoO phase. After annealing at 500 °С more than 80% of Co was reduced and the final product contained Co nanoparticles above and below the superparamagnetic critical size embedded into a dielectric ZrO 2 matrix. The synthesized Co–ZrO 2 nanocomposite films possessed soft magnetic behavior, high magnetization and good chemical stability.

The evolution of the structural and magnetic properties in epitaxial film systems Co/Pt(111) of equiatomic composition during vacuum annealing has been presented. Annealing to the temperature of 400°C does not lead to the variation of the structural and magnetic properties of the films, which indicates the absence of considerable mixing of the Co/Pt interface. With the increase in the annealing temperature from 400 to 750°C, nanoclusters containing the main magnetically hard L10CoPt(111) phase epitaxially intergrown with the CoPt3 phase are formed. High rotatable magnetic anisotropy has been found in the prepared films. In magnetic fields above the coercive force (H > H C = 8 kOe), the easy anisotropy axis with the angle of lag taken into account can be oriented in any spatial direction. Possible mechanisms of the formation of the rotatable magnetic anisotropy have been discussed. It has been assumed that the high rotatable magnetic anisotropy makes the main contribution to the magnetic perpendicular anisotropy in Co x Pt1–x films.

Fe–ZrO 2 ferromagnetic nanocomposite thin films are successfully synthesized using a thermite reaction between the Zr and Fe 2 O 3 layers. The initial Zr/Fe 2 O 3 bilayers were obtained by the deposition of Zr layers on α-Fe 2 O 3 films at room temperature. The mixing at the Zr/Fe 2 O 3 interface and synthesis of α-Fe and the amorphous ZrO 2 phases start at a temperature above the initiation temperature T in ∼ 250 °C. Together with the formation of α-Fe, partial transformation from Fe 2 O 3 to Fe 3 O 4 occurs after annealing at 300 °C. The secondary reaction between Fe 3 O 4 and Zr starts soon after the Fe 2 O 3 is converted to the Fe 3 O 4 phase. The crystallization of amorphous ZrO 2 and the formation of the ZrO 2 cubic/tetragonal phase occurs above 400 °C. After annealing at 500 °C the reaction products contain (1 1 0) textured α-Fe nanocrystals with a diameter of about 34 nm embedded in an insulating c-ZrO 2 (or t-ZrO 2 ) matrix. The synthesized Fe–ZrO 2 nanocomposite films possess soft magnetic behavior, high magnetization and good chemical stability.

The solid-state reaction between epitaxial hcp-Co (110) and fcc-Co (001) thin films and Pd layers was investigated at annealing temperatures between 250 and 650 °C using X-ray diffraction and magnetic measurements. No significant intermixing of the layers occurs at annealing temperatures below 400 °C. For the atomic composition 1Co:1Pd after annealing at 450 °C the disordered solid solution fcc-CoxPd1-x is formed on the Pd/hcp-Co (110) and Pd/fcc-Co (001) interfaces. Epitaxial relationships CoPd (110)〈-111〉 || MgO(001)〈100〉 and CoPd (001)〈100〉 || MgO(001)〈100〉 between the nucleated disordered phase CoPd and the substrate MgO(001) were determined for Pd/hcp-Co (110) and Pd/fcc-Co (001) bilayers, respectively. The first magnetocrystalline anisotropy constant of the disordered CoPd phase ​​K1CoPd = - (1.8 ± 0.4)·104 J/m3 for the (110) and (001) orientations was obtained.

The results of the investigation of the structural and magnetic properties of CoPd films with equiatomic composition have been presented. The films have been synthesized by vacuum annealing of polycrystalline Pd/Co and epitaxial Pd/α-Co(110) and Pd/β-Co(001) bilayer samples. It has been shown that, for all samples, the annealing to 400°C does not lead to the mixing of layers and the formation of compounds. A further increase in the annealing temperature results in the formation of a disordered CoPd phase at the Pd/Co interface, which is fully completed after annealing at 650°C. The epitaxial relationships between the disordered CoPd phase and the MgO(001) substrate are determined as follows: CoPd(110)〈 $$\bar 111$$

The structural and magnetic properties of ZnO-Fe3O4 nanocomposites produced by the solid-state reaction Zn + 3Fe2O3 → ZnO + 2Fe3O4 upon annealing of Zn/α-Fe2O3 films under vacuum at a temperature of 450°C have been studied. Ferrimagnetic Fe3O4 clusters with an average grain size of 40 nm and a magnetization of ∼430 emu/cm3 at room temperature, which are surrounded by a ZnO layer with a large contact surface, have been synthesized. The magnetic characteristics of the ZnO-Fe3O4 nanocomposite in the temperature range of 10–300 K have been presented.

We have successfully synthesized ferromagnetic Fe–In 2 O 3 nanocomposite thin films for the first time using the thermite reaction Fe 2 O 3 + In = In 2 O 3 + Fe. The initial In/Fe 2 O 3 bilayers were obtained by the deposition of In layers on α-Fe 2 O 3 films. The reaction occurs in a self-propagating mode in a homogeneous thermal film plane field at heating rates above 20 K/s and at temperatures above initiation temperature T in ∼ 180 °С. At heating rates lower than 20 K/s the mixing of the In and Fe 2 O 3 layers occurs across the whole In/Fe 2 O 3 interface and the synthesis of the ferromagnetic α-Fe phase starts above the initiation temperature T in = 180 °С. X-ray diffraction, X-ray photoelectron spectroscopy, Mossbauer spectroscopy, transmission electron microscopy and magnetic measurements were used for phase identification and microstructure observation of the synthesized Fe–In 2 O 3 samples. The reaction products contain (1 1 0) textured α-Fe nanocrystals with a diameter around 100 nm and surrounded by an In 2 O 3 matrix. These results enable new efficient low-temperature methods for synthesizing ferromagnetic nanocomposite films containing ferromagnetic nanoclusters embedded in transparent conducting oxides.

Solid-state reactions between Ge and Mn films are systematically examined using X-ray diffraction, photoelectron spectroscopy and magnetic measurements. The films have a nominal atomic ratio Ge:Mn = 40:60 and are investigated at temperatures from 50 to 500 °С. It is established that after annealing at ~120 °С, the ferromagnetic Mn5Ge3 phase is the first phase to form at the 40Ge/60Mn interface. Increasing the annealing temperature to 500 °С leads to the formation of the ferromagnetic phase with a Curie temperature TC ~ 360 K and magnetization MS ~ 140-200 emu/cc at room temperature. Analysis of X-ray diffraction patterns and the photoelectron spectra suggests that the increased Curie temperature and magnetization are related to the migration of C and O atoms into the Mn5Ge3 lattice and the formation of the Nowotny phase Mn5Ge3СxOy. The initiation temperature (~120 °С) of the Mn5Ge3 phase is the same both for solid-state reactions in Ge/Mn films, as well as for phase separation in GexMn1-x diluted semiconductors. We conclude that the synthesis of the Mn5Ge3 phase is the moving force for the spinodal decomposition of the GexMn1-x diluted semiconductors.

The dispersions of semiconducting (sc-) and metallic (m-) SWCNTs with purity more than 98 and 86%, correspondingly, were obtained by using the aqueous two-phase extraction method. The unseparated (un-) SWCNTs contained ~3/4 of semiconducting and ~1/4 of metallic nanotubes. Thin films based on unseparated, semiconducting and metallic SWCNTs were prepared by vacuum filtration method. An Atomic Force Microscopy (AFM) and a Transmission Electronic Microscopy (TEM) were used to investigate the thin film microstructure. The thin SWCNT film transmittance was measured in the wavelength range of 300–1500 nm. Thermoelectric properties were carried out in the temperature range up to 200 °C. The largest Seebeck coefficient was observed for thin films based on semiconducting SWCNTs. The maximum value was 98 μV/K under the temperature of 170 °C. The lowest resistivity was 7.5·10−4·Ohm·cm at room temperature for thin un-SWCNT films. The power factor for m-SWCNT and un-SWCNT films was 47 and 213 μW m−1 K−2, correspondingly, at room temperature and 74 and 54 μW m−1 K−2 at 200 °C, respectively. For a thin sc-SWCNT film the maximum power factor was 2.8 μW m−1 K−2 at 160 °C. The un-SWCNT film thermal conductivity coefficient was 5.63 and 3.64 W m−1 K−1 and a thermoelectric figure of merit was 0.011 and 0.016 at temperatures of 23 and 50 °C, respectively.

A ferromagnetic Fe–In2O3 nanocomposite thin film has been synthesized by the thermite reaction Fe2O3+In→Fe–In2O3. Measurements of the Hall carrier concentration, Hall mobility and magnetoresistance have been conducted at room temperature. The nanocomposite Fe–In2O3 thin film had n=1.94·1020 cm−3, μ=6.45 cm2/Vs and negative magnetoresistance. The magnetoresistance for 8.8 kOe was ~−0.22%.The negative magnetoresistance was well described by the weak localization and model proposed by Khosla and Fischer.

Indium-oxide films are synthesized by the autowave-oxidation reaction. It is shown that, upon exposure to optical radiation, the resistance of the films sharply decreases and the maximal relative change in the resistance is 52% at room temperature. Two resistance relaxation rates after termination of the irradiation, 15 Ω s−1 during the first 30 s and 7 Ω s−1 over the remaining time, are determined. The data of infrared spectroscopy of the films show that exposure to optical radiation induces a 2.4% decrease in the transmittance at a wavelength of 6.3 μm. It is found that, after termination of the irradiation, the transmittance gradually increases with a rate of 0.006% s−1. It is suggested that photoreduction is the dominant mechanism responsible for changes in the electrical and optical properties of the In2O3 films.

Cubic-phase In2O3 films are produced by the autowave oxidation reaction. Electron microscopy and photoelectron spectroscopy of the atomic profiles show that the samples are homogeneous over the entire area and throughout the thickness, with the typical grain size being 20–40 nm. The optical and electrical properties are studied for In2O3 films fabricated at different pressures in the vacuum chamber. In the wave-length range from 400 to 1100 nm, the transparency of the films was higher than 85%; the resistivity of the films was 1.8 × 10−2 Ω cm.

Текст статьи не публикуется в открытом доступе в соответствии с политикой журнала. Solid-phase transformations at different annealing temperatures in Mn/Bi (Mn on Bi) and Bi/Mn (Bi on Mn) films have been studied using X-ray diffraction, electron microscopy, and magnetic measurements. It has been shown that the synthesis of the α-MnBi phase in polycrystalline Mn/Bi films begins at a temperature of ~120°C and the Mn and Bi layers react completely at 300°C. The resulting α-MnBi(001) samples have a large perpendicular magnetic anisotropy (Ku ≃ 1.5 × 107 erg/cm3) and a coercive force H > HC ~ 3 kOe. In contrast to Mn/Bi, the ferromagnetic α-MnBi phase in Bi/Mn films is not formed even at annealing processes up to 400°C and Mn clusters are formed in a Bi melt. This asymmetry in phase transformations occurs because chemosorbed oxygen existing on the surface of the Mn film in Bi/Mn films suppresses a solid-phase reaction between Mn and Bi. The analysis of the results obtained implies the existence of new low-temperature (~120°C) structural transformation in the Mn–Bi system. Твердофазные превращения в зависимости от температуры отжига в Mn/Bi (Mn на Bi) и Bi/Mn ( Bi на Mn) пленках исследовались с использованием рентгеновской дифракции, электронной микроскопии и магнитных измерений. Показано, что синтез альфа-MnBi фазы в поликристаллических Mn/Bi пленках начинается при при температуре 120 К и при 300 К слои Mn и Bi реагируют полностью. Полученные образцы альфа-MnBi(001) обладали большой перпендикулярной анизотропией и большой коэрцитивной силой H>Hc =3 kЭ. В отличие от Mn/Bi в пленках Bi/Mn даже при отжигах до 400 С ферромагнитная альфа-MnBi фаза не образовывалась, а наблюдалось образование кластеров Mn в расплаве Bi. Данная асиметрия в фазовых превращениях объясняется существованием в пленке Bi/Mn на поверхности Mn хемосорбционного кислорода, который подавляет твердофазную реакцию между Mn и Bi. На основании анализа результатов проведенныъх исследований предполагается существование низкотемпературного (120 С) структурного превращения в Mn-Bi-системе.

The negative magnetoresistance of thin In 2 O 3 films, obtained by an autowave oxidation reaction, was detected within a temperature range of 4.2–80 K. The magnetoresistance was –1.35% at a temperature of 4.2 K and an external magnetic field of 1 T. A weak localization theory was used to explain the negative magnetoresistance and to determine the phase-coherence length in a temperature range of 4.2–80 K. The phase-coherence length was found to oscillate as the temperatures increased to around 30 K. From the maximum and minimum values of the oscillation of the phase-coherence length, it was suggested that the In 2 O 3 film has two structure characteristic parameters. Transmission electron microscopy showed the structure of the thin In 2 O 3 film to have structural features of a «crystal phase – amorphous phase». It was found that the crystalline phase characteristic size was consistent with the maximum phase-coherence length and the amorphous phase characteristic size was consistent with the minimum phase-coherence length. It has been suggested that the temperature measurements of the magnetoresistance and the theory of weak localization can be used to evaluate the structural features of nanocomposite or nanostructured thin films.