The features of the magnetic state of an array of parallel oriented permalloy ribbons are discussed. The arrays are made by explosive lithography. The ribbons have a thickness of 180 nm, a width of ...2.8 µm, and a length of about 4 mm. The distance between ribbons in different samples varies in the range from 300 nm to 4 μm. It is found that the ribbons in the regions far from the end faces are in a single-domain state with small-angle ripples, the magnetization distribution of which correlates with inhomogeneities of the ribbon side surfaces. Moreover, there is a distinct relationship in the spatial distribution of the ripples between adjacent ribbons with a relatively small distance between them. This makes it possible to evaluate the role of the magnetostatic coupling of magnetic subsystems of array elements and to estimate the characteristic value of the random stray field that pins the magnetization.
Composite materials based on PbO2 containing TiO2 or ZrO2 were prepared from electrolytes containing a suspension of TiO2 or ZrO2. The contents of foreign oxides in the composite depend on the ...electrolyte composition and conditions of deposition. When a dispersed phase is incorporated into the composite coating, the dimensions of lead dioxide crystals decrease to submicro- and nano-size. Physico-chemical properties of composite materials are mainly determined by their chemical composition.
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.
The problem of modeling real logistics systems arranged in a hierarchical manner is considered. Clusters of lower level consumers are formed that meet the time window (TW) constraints for each ...consumer and the cluster as a whole. In each such cluster, a traveling salesman’s route is constructed and the vertex closest to the central node, which is the vertex of reloading goods from heavy vehicles (Vs) to light Vs serving consumer clusters, is selected. The transshipment vertices, in turn, are combined into higher level traveling salesmen’s routes, taking into account TWs for routes of this level. The software implementation is tested on well-known networks. The technique is applicable for the synthesis of the central distribution center and system distribution centers of the lower level, as well as for calculating the required number of vehicles (agents).
The influence of the synthesis conditions on the surface morphology, phase composition, and electrocatalytic activity of materials in oxygen and hydrogen evolution reactions was investigated. For ...instance, the slopes in the potential verses the logarithm of the current density dependencies during oxygen evolution were 221 and 109 mV/dec for TiO
2
nanotubes and platinum-coated layers, respectively. In the latter case, small deviations may be attributed to the structural heterogeneity of the material or the developed surface of the coating. As for pristine TiO
2
nanotubes, an atypical Tafel slope was observed, almost twice the theoretical value, indicating the presence of a semiconductor component in the electrode capacitance. Studies showed that the materials are n-type semiconductors. The cathodic polarization stage leads to the formation of titanium suboxides in the nanotube recovery phase, contributing to an increase in the material electrical conductivity. This also allows for the creation of a porous developed surface matrix for the electrodeposition of catalytic metal layers. Tafel slopes were calculated for the investigated materials in the hydrogen evolution reaction. For TiO
2
nanotubes, a slope of 175 mV/dec was observed. The material surface was partially blocked by hydroxides, resulting in a low number of active centers for the hydrogen evolution, and the polarization curve had a steep slope. In the case of TiO
2
nanotubes coated with a platinum layer, a high number of cationic vacancies in the matrix and a deficit of oxygen ions facilitated the mobility of platinum atoms, leading to the emergence of a large number of active centers for the hydrogen evolution. As a result, the Tafel slope of the polarization curve was found to be 30 mV/dec.
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
S
11
,
S
21
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.
Graphical abstract
Mn
5
Ge
3
is a ferromagnetic hexagonal crystal promising for spintronics and magnetocalorics. A systematic study and analysis of the magnetic properties of the Mn
5
Ge
3
thin film grown on Si(111) ...were performed. The magnetic anisotropy of the film is determined by the shape anisotropy and the easy magnetization axis aligned along the
c
axis of the crystal. The uniaxial anisotropy constant
K
u
fully corresponds to that for a bulk single crystal, which indicates that
c
axis coincides with film normal. Mn
5
Ge
3
film demonstrates high saturation magnetization
M
S
= 900 emu/cm
3
(900 kA/m) at
T
= 100 K and magnetocaloric effect Δ
S
= 3.16 ± 0.22 J kg
−1
K
−1
at 300 K and
B
= 1.5 T. Δ
S
is comparable to that for multicomponent or Gd rare earth films. Furthermore, a different anisotropy of the magnetocaloric effect compared to bulk Mn
5
Ge
3
was found, which may be related to the anisotropy of the film shape and, possibly, to the domain structure. The results obtained are promising for the design and development of magnetocaloric, spintronic, and spin-caloritronic devices on a silicon platform.
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