bluuebunny/crossref_metadata_2025 huggingface dataset:
Good practice guide around the security of the internet of things in smart homes
Authors: Sánchez-Pérez L M , Velásquez-Pérez T , Camargo-Pérez J C
Published: November 2019

This article presents a guide to good practices around internet safety of things for devices that get involved with smart homes. It is chosen to use a quantitative methodology of descriptive approach, taking into account that it is a topic that is in incursion and it is necessary to begin to establish the elements that are going to incorporate in the guide. The starting point is a study of the internet layers of things, the open web application security project and the components that make up the guide. This research allows to make a contribution with an analysis of the future of the internet of things and to expose the considerations on the security that involve these devices, taking as guide the tools, documents and information that the project proposes for the development of systems of high quality in security.
Effects of climate change on the resources of the rural ecosystem, a view from farmer perspectives
Authors: Núñez R J J
Published: November 2019

This paper presents the results obtained from the categorization of the social representations of farmer groups on the effects of climate change on the biodiversity of their farms, developed in a rural area of the Colombian Andes. A mixed methodology was used throughout the analysis of the behavior of rainfall and temperature between the years 2010-2017 and the implementation of an open survey on 144 farmers, of which its data was analyzed using descriptive and inferential statistics through descriptive estimators and an analysis of variance and multiple comparison mean tests, respectively. Furthermore, a qualitative analysis, supported by Corbin and Strauss’ Grounded Theory, was carried out on 18 farmer families using semi-structured interviews. The hypothesis testing determined the existence of significant differences between the mean temperatures of the years observed when obtaining a value of Fc = 3.50, highly significant at 1%, and a value of Fc = 2.79, significant at 5%, P<0.05, for the mean rainfall. In the descriptive analysis, farmers’ perception of the negative effects of climate change was evident in the decrease in the availability of water from natural sources (80.6%), deterioration in water quality (50.0%), variations in rainfall intensity (82.0%) and in local bimodal rainfall patterns (79.0%). The inferential analysis determined that the proportion of farmers reporting a disappearance of species due to intense heat or rainfall differs significantly from the level of p<0.05, over those who reported that these conditions have not caused variations in flora and fauna. The qualitative analysis verified the effects of climate change on rural biodiversity resources, which were expressed in 4 emerging categories: 1) Biodiversity resources in the process of extinction, 2) resilient resources, 3) emerging biodiversity, and 4) new agricultural business opportunities. The findings reveal that from a farmers’ perspective climatic variations are affecting species of fauna and flora in rural communities.
Unidirectional motion of magnetic domain walls: the experiment and numerical simulation
Authors: Pamyatnykh L A , Lysov M S , Pamyatnykh S E , Mekhonoshin D S , Agafonov L Yu , Shmatov G A
Published: November 2019

The results of study of unidirectional motion of topologically different domain structures under the influence of periodic bipolar and unipolar magnetic field pulses applied perpendicular to the sample plane of (111) iron garnet single crystal plate are presented. The response of the domain structure to the field pulses was studied by direct observations utilizing the stroboscopic technique. Experimentally obtained dependences of the speed of unidirectional motion of stripe domains on the parameters of external bipolar pulsed magnetic field are compared with the results of numerical simulations.
One-dimensional dynamics of magnetic inhomogeneities in a three- and five-layer ferromagnetic structure with different values of the magnetic parameters
Authors: Gumerov A M , Ekomasov E G , Kudryavtsev R V
Published: November 2019

The article presents the research results of localized magnetization waves dynamics in five-layer and three-layer ferromagnetic structures. Structures consisting of three or two wide identical magnetic layers separated by two or one thin magnetic layer with the magnetic parameters values changed relative to wide layers are considered. The magnetic anisotropy, exchange, and damping parameters are considered to be the functions of the coordinate perpendicular to the interfaces. Intermediate layers are assumed to be infinitely thin. The considered magnetic material has homogeneous magnetic parameters everywhere, except for the planes corresponding to the interlayers. Using the approximate collective-coordinate method, the dynamics of coupled nonlinear magnetization waves localized on thin layers is theoretically studied.
Dynamics of magnetization in an array of three-layer nanodiscs
Authors: Orlov V A , Patrin G S , Orlova I N
Published: November 2019

The paper studies associated motion of magnetic vortices in a triple-layer FM/NM/FM disc array. The connection of magnetic layers’ magnetization inside of one disc and between the discs is assured by magnetostatic interaction. The frequencies of magnetic vortex resonant motion have been calculated analytically and resonant curves for the arrays with different alternation of magnetic vortex polarity and chirality have been constructed. It has been shown that despite of a small value of the core magnetic moments, taking their interaction into account leads to a small but significant splitting of the resonant frequency.
Frustrations and orderings in Ising chain with multiple interactions
Authors: Zarubin A V , Kassan-Ogly F A , Proshkin A I
Published: November 2019

The frustration properties of the Ising model on a one-dimensional monoatomic equidistant lattice are investigated taking into account the exchange interactions of atomic spins at the sites of the first (nearest), second (next-nearest) and third neighbors. The exact solution of the model was obtained using the Kramers–Wannier transfer matrix method. The types of magnetic ordering of the ground state of the model are determined, and a magnetic phase diagram is constructed. Criteria are formulated for the occurrence of magnetic frustrations in the presence of competition between the energies of exchange interactions. Non-zero entropy values in the ground state of the frustrated system were found.
Phase transitions in the two-dimensional four-vertex Potts model with quenched nonmagnetic impurities
Authors: Babaev A B , Murtazaev A K
Published: November 2019

The thermodynamic properties and phase transitions in the two-dimensional weakly diluted Potts model with the number of spin states q=4 were studied by the Monte Carlo method. Systems with linear dimensions L×L = N, L=10–160 are considered. Using the fourth order Binder cumulant method, critical temperatures were calculated for spin systems with a spin concentration p=1.0 and 0.90. Critical indices are calculated on the basis of the theory of finite-size scaling. The universality of the critical behavior of two-dimensional disordered systems is discussed.
Polarization selection in Mössbauer reflectivity for magnetic multilayer investigation
Authors: Andreeva M A , Baulin R A , Slinko O V , Häggström L , Asadchikov V E , Karimov D N , Roshchin B S , Ponomarev D A , Romashev L N , Chumakov A I , Bessas D , Rüffer R
Published: November 2019

Mössbauer reflectivity experiment with polarization selection are reported. The use of the LiF polarization analyzer allows us to get the π→σ’ peak on the reflectivity curve at the critical angle and Mössbauer π→σ’ reflectivity spectra of reasonable quality at the critical angle and also at the Bragg angles of superlattice. The impressive difference of the reflectivity spectra measured near the critical angle with and without polarizations analysis is observed for [57Fe10/V10]20 multilayer characterizing by the ferromagnetic interlayer coupling. The combined fit of the whole set of spectra measured at different angles reveals the existence of antiferromagnetic Fe oxide phases in the top three bilayers. The experiment demonstrates benefits of the Mössbauer reflectivity with polarization analysis in ultrathin surface layer investigations.
Magnetic anisotropy and magnetoelastic properties of Fe10Ni90 films
Authors: Kudyukov E V , Balymov K G , Vas’kovskiy V O
Published: November 2019

This work is devoted to studying the effect of the thickness and type of the buffer sublayer on the magnetic anisotropy and the magnetoelastic properties of Fe10Ni90 films. It is established that the anisotropy of Fe films strongly depends on thickness, which can be associated with the influence of several mechanisms of anisotropy formation. Measurements of the magnetostriction of thin films using magnetoresistive curves were made. The value of the magnetostriction constant also depends on the thickness of the films.
The dimensional crossover in critical behavior of layered XY-model
Authors: Popov Ivan S , Popova Anna P , Prudnikov Pavel V
Published: November 2019

The study of critical properties and size transition in a diluted layered XY-model was carried out for the first time. The dimensional dependence of the temperature T
BKT(p, N) of the Berezinskii-Kosterlitz-Thouless phase transition on the system thickness N is obtained for a diluted layered XY-model for a wide range of spin concentrations p. The temperature T, concentration p, and dimensional N dependencies of the vortex density v(p, N, T) in a layered XY-model are obtained.
Magnetic state and magnetic hysteresis in the molybdenum diselenide intercalated with chromium atoms
Authors: Pleshchev V G , Neznakhin D S , Flyagin V S , Selezneva N V
Published: November 2019

In this work intercalated compounds in the Cr-MoSe2 system were synthesized for the first time. Their magnetic properties are studied at various intercalant concentrations, temperatures and magnetic fields. The temperature dependences of effective magnetic moments and positive paramagnetic Curie temperatures in the paramagnetic region evidence the feasible ferromagnetic interactions between intercalated atoms. The existence of low-temperature ferromagnetic state in CrxMoSe2 is confirmed by hysteresis phenomena in temperature dependences magnetic susceptibility and field dependences of magnetization. The change in the magnetic state affects the character of the temperature dependences of the resistivity.
Complex application of magnetic and magnetoacoustic parameters in the structuroscopy of ferromagnetic materials
Authors: Kostin V N , Serbin E D , Vasilenko O N
Published: November 2019

The set of magnetic parameters and amplitude-frequency spectral characteristics of magnetoacoustic emission (MAE) of a large group of metal ferromagnetic materials differing in their physical properties and size are investigated. It is shown that the change in critical fields determined by the shape of the magnetization curve and the hysteresis loop of bulk samples with an increase in the annealing temperature of cold-deformed steel 20G is 1.5–3 times greater than the change in such well-known parameters for estimating the stress-strain state, such as coercive force and residual magnetic induction. It has been established that the amplitude of magnetoacoustic emission correlates with the residual magnetic induction, which makes it possible to recommend the complex application of these testing parameters in scanning systems of structuroscopy of ferromagnetic materials.
Phonon anomaly in Sm2BaNiO5
Authors: Klimin S A , Popova E A , Popova M N
Published: November 2019

We present low-temperature far-infrared study of Sm2BaNiO5. The lowest-frequency phonon of Sm2BaNiO5 generated by the motion of the Sm3+ ion demonstrates anomalous behaviour at temperatures lower than the Néel temperature, T<T
N=55 K. This phonon hardens at the magnetic ordering although its frequency shift does not follow the magnetic order parameter. The observed phenomenon is responsible for an unusual dielectric response of Sm2BaNiO5 reported in the literature. A correlation between the temperature behaviour of crystal-field levels and the phonon anomaly is discussed.
Terahertz modulation of the Cotton-Mouton effect
Authors: Barsaume S , Mashkovich E A , Grishunin K A , Telegin A V , Sukhorukov Y P , Christianen P C M , Rasing Th , Kimel A V
Published: November 2019

The ultrafast dynamics of the magneto-optical response triggered in the ferromagnetic semiconductor CdCr2Se4 by an intense nearly single cycle THz pulse is investigated. The dependence on the strength and the polarity of the external magnetic field, and the polarization of the THz pulse can be explained by a phenomenological expression that attributes the observed dynamics to the Cotton-Mouton effect at THz frequencies.
Structure and magnetic properties of LiNi1-xCoxPO4 magnetoelectrics with x = (0, 0.1, and 0.2)
Authors: Semkin M A , Urusova N V , Lee S , Kalinkin M O , Kuznetsov D K , Kulesh N A , Neznakhin D S , Kellerman D G , Pirogov A N
Published: November 2019

We present the magnetic properties of LiNi1-xCoxPO4 magnetoelectrics, with x = (0–0.2), and their analysis of concentration dependences. Samples have been synthesized by a glycerol-nitrate method. To refine crystal structure X-ray diffraction measurements were carried out. Magnetic measurements were performed at the external magnetic field of 500 Oe over the temperature range (2–300) K. The neutron powder diffraction patterns of LiNi0.9Co0.1PO4 were recorded over temperature interval from 4.4 K up to 25 K. The partial doping in the LiNi1-xCoxPO4 magnetoelectrics the Ni ions for Co ions leads to a narrowing of the temperature interval where the incommensurate phase is established.
Effect of particle diameter and packing density on heating of metallic iron particles in alternating magnetic field
Authors: Krekhno Roman V , Safronov Alexander P , Beketov Igor V
Published: November 2019

The heat losses originated from the electro-magnetic absorption in mechanically packed metallic iron nano- and micro-sized magnetic particles (MPs) and in magnetic epoxybased composites with embedded MPs were studied by Calvet microcalorimetry. Nano-sized MPs with numerical average diameter 40 nm were synthesized by electrical explosion of wire method; micro-sized MPs with numerical average diameter 2 μm were synthesized by flame decomposition of the iron pentacarbonyl. The specific loss power (SLP) of re-magnetization of press-packed powdered samples and epoxy composites in magnetic field 1750 A/m at 214 kHz was measured as a function of the volume fraction of MPs in the sample. The results showed up that SLP depended both on particle size and on volume fraction, which meant the significant effect of magnetic interaction among particles on the heat losses in electromagnetic absorption.
Stratification of ferroparticles caused by gravitational and magnetic fields in soft ferronematics
Authors: Petrov Danil A , Makurin Alexey V
Published: November 2019

In the framework of continuum theory we study the magnetic particles stratification caused by gravitational and magnetic fields in ferronematic, i.e., a highly dispersed suspension of ferroparticles in a nematic liquid crystal. We consider the so-called soft ferronematic, where the coupling energy between the liquid crystal and the particle surfaces is finite, which allows to consider the director and magnetization of the ferronematic as independent variables. We show how under the influence of an external uniform magnetic field due to the segregation effect heavy impurity ferromagnetic particles begin to float up in a lower-density fluid, moving opposite to the gravity field. As an example, several types of suspensions with material parameters corresponding to actually synthesized ferronematics with different ratios between the two competing mechanisms of separation of impurity particles (segregation and gravity) are considered.
Influence of temperature on the impurity-induced s± → s++ transition in the two-band model for Fe-based superconductors
Authors: Shestakov Vadim , Korshunov Maxim M
Published: November 2019

In Fe-based superconducting materials, the s
± state with the sign-changing gap in the clean limit could be changed to the sign-conserving s
++ state by nonmagnetic impurities. Previous results are obtained for the fixed temperature well below the superconducting critical temperature Tc
. We study how the increasing temperature affects the transition between s
± and s
++ states in the two-band model. The calculations show that the s
± → s
++ transition appears to be dependent on temperature T, i.e. there exists a narrow range of impurity scattering rates, where the s
++ state in dirty superconductor at low temperature is transformed back to the s
± state by increasing T. With the nonmagnetic impurity scattering rate increasing, the temperature of such a reverse transition is shifted to Tc
, while the s
++ state remains solely one for higher degree of disorder.
Spin-fluctuation mechanism of superconductivity in Ba(Fe1-xCox)2As2 ferropnictides
Authors: Karakozov A E , Magnitskaya M V , Mikheenkov A V , Kadyrov L S , Gorshunov B P
Published: November 2019

Gap structure and spin-fluctuation pairing mechanism in the iron-based superconductors Ba(Fe1-xCox)2As2 is studied. We demonstrate that the overdoped compounds Ba(Fe1-xCox)2As2 have a three-gap structure with substantially different order parameters and a weak interband spin-fluctuation coupling. In the three-gap state of Ba(Fe1-xCox)2As2, the anisotropic electronic gap has an intermediate value between two isotropic hole gaps. During transition to the optimal regime, the electron gap strongly increases (by a factor of two) and gets close to the largest hole gap value, while the electron gap anisotropy sharply decreases pointing to a strong increase in the interband interaction, with spin fluctuations accompanying the antiferromagnetic transition. The same two-gap state with close values of the electron and largest hole gaps is preserved even with further decrease in doping. The performed study shows that the spin-fluctuation pairing mechanism has a significant effect on doping evolution of the electron gap only. The doping evolution of the dominant hole gap in Ba(Fe1-x
Co
x
)2As2 is not directly related to the evolution of the spin fluctuations.
Electronic structure of BaBiOß: QMC CT-INT algorithm
Authors: Lukyanov Alexander , Neverov Vyacheslav , Krasavin Andrey , Zhumagulov Yaroslav
Published: November 2019

The continuous time quantum Monte Carlo algorithm with interaction expansion is implemented for Hubbard-Holstein model. Algorithm is approbated on the Bethe lattice with exact diagonalization technique and then is applied to calculate the self-energy of the BaBiO3 compound.
First-principles study of the structure and properties of Fe-Rh-Ir alloys
Authors: Pavlukhina O O , Sokolovskiy V V , Buchelnikov V D , Zagrebin M A
Published: November 2019

The magnetic and structural properties of FeRh1-xIrx (x = 0.125, 0.25, 0.375, and 0.5) alloys were studied using ab initio calculations. The two structure types (CuAu and CsCl) were considered. The equilibrium lattice parameters, total energy and magnetic moments as well as total and partial densities of states for Fe-Rh-Ir with different magnetic ordering were obtained. It is shown that the CuAu-type structure with AF-III configuration is energetically favourable for all compositions under study. The spin polarization at the Fermi level for FeRh0.125Ir0.875 ordered ferromagnetically is found to be 85 %.
Multicomponent alloys with thermally, mechanically and magnetically controlled shape memory effects
Authors: Okulov A V , Belosludtseva E S , Kuranova N N , Marchenkova E B , Pushin A V , Pushin V G
Published: November 2019

This paper presents a brief review of the systematic study of the influence of the chemical composition on the structure, phase transformations and physical properties of binary and quasi-binary Ti-Ni, TiNi-TiFe, TiNi-NiCu, NiMn-NiGa and Ni2MnGa-Ni3Ga systems, which undergo thermoelastic martensitic transformations (TMT) and related with them thermally, mechanically, or magnetically controlled shape memory effects (SME). The effect of alloying with a third component on the behavior of critical temperatures and the TMT sequence has been established, and their generalized diagrams have been constructed. It is shown that the morphology of thermoelastic martensite is a hierarchy of packets of thin coherent crystals.
Quantization of the anomalous Hall conductance in a disordered magnetic Chern insulator
Authors: Novokshonov Sergey
Published: November 2019

The intrinsic anomalous Hall conductance

σ

x
y

int

of a minimal model of the twodimensional disordered Chern insulator is investigated in the framework of Kubo quantum theory of linear response. The electron momentum relaxation is assumed to be due to electron scattering by Gaussian white-noise potential. The explicit expressions for the density of states and

σ

x
y

int

are obtained in the self-consistent Born approximation. The numerical analysis of these expressions at the different values of parameters of the considered model shows that calculated

σ

x
y

int

takes a quantized value e
2/4πħ when the Fermi level lies within the energy gap. This gap is narrowed as disorder increases that leads to decreasing of the Hall plateau width.
Inhomogeneuos state of ferrimagnetic film near compensation point
Authors: Kudasov Yu B , Kozabaranov R V
Published: November 2019

Recently, an investigation of the Faraday rotation in thin iron garnet film (LuBi)3(FeAlGa)5O12 revealed an unusual “precursor” of transition to a noncollinear phase. It was observed in the vicinity of the compensation temperature. However, this feature cannot be ascribed to the uniform phase transition associated with uniaxial anisotropy. A model for the “precursor” based on inhomogeneous magnetic structure at the substrate-film interface is presented. To interpret the Faraday rotation, two diamagnetic optical transitions attributed to tetrahedral and octahedral iron sublattices are considered.
Thickness dependences of coercivity in three layer films obtained by chemical deposition
Authors: Chzhan A V , Podorozhnyak S A , Shahov A N , Velikanov D A , Patrin G S
Published: November 2019

The change of the coercivity Hc of three-layer films obtained by chemical deposition depending on the thickness of the nonmagnetic interlayers and magnetic layers are presented. Structures with magnetically identical soft layers, as well as with significantly different HC values were investigated. It was established that in both cases thecoercivity decreases with the interlayer thickness increasing by an exponential law. It is consistent with a change in the displacement field of the hysteresis loop. The observed changes in the parameters of the hysteresis loop are associated with the roughness of the interfaces.
Magnetic, electric properties and hardness of 17-4 PH stainless steel fabricated by selective laser melting
Authors: Stashkov A , Schapova E , Tsar’kova T , Sazhina E , Bychenok V , Fedorov A , Kaigorodov A , Ezhov I
Published: November 2019

This research examines 17-4 PH stainless steel (SS) samples fabricated by selective laser melting (SLM). The samples were built in vertical direction, and it was necessary to load powder three times. This made the process suspended and led to the changes in temperature conditions. Despite a continuity of the samples, the samples were divided into three parts shared by visible interfaces. The samples were examined by optical microscopy and X-ray diffraction (XRD) analysis. The XRD data showed variations in phase compositions over the samples height. Magnetic and electric properties, hardness and microhardness of the samples in each parts were determined before and after the heat treatment (650 °C for 1 hour, cooling in a furnace). Obtained results show an inhomogeneity of properties over the samples height, but heat treatment led these properties to be uniformly distributed.
Incommensurate-commensurate magnetic phase transitions in Tb1-xErxNi5 compounds
Authors: Pirogov A , Lee H , Choi Y N , Gerasimov E , Lukoyanov A , Bogdanov S
Published: November 2019

Spontaneous and magnetic field induced incommensurate – commensurate magnetic phase transitions have been studied in Tb1-x
Er
x
Ni5 compounds near the critical concentration x
c = 0.125. Compounds crystallize in the hexagonal CaCu5 type phase (P6/mmm space group). In compounds with x ≥ x
c the magnetic order is a commensurate ferromagnetic one. The samples with x < x
c have an incommensurate structure that is a fan like magnetic structure and described by two propagation vectors. An incommensurate – “lock in” magnetic transition takes place at 10 K at cooling regime.
Modeling of magnetoimpedance effect in nanostructured multilayered films
Authors: Buznikov N A , Kurlyandskaya G V
Published: November 2019

The magnetoimpedance effect in nanostructured multilayers is studied theoretically. The multi-layered film structure consists of highly conductive non-magnetic central layer and two external multilayers containing soft magnetic layers of the same thickness separated either by magnetic spacers of different kind or by non-magnetic spacers. In order to describe the magnetoimpedance in the multilayer an electrodynamic model is proposed. The influence of geometric parameters and physical properties of the layers on the magnetoimpedance response is analyzed. The results obtained could be useful both for better understanding of high-frequency behavior of nanostructured multilayers and for optimization of multilayer parameters aiming to enhance the magnetoimpedance effect for practical applications.
Calculation of SWR spectra in two- and three-layer magnetic films
Authors: Bazhanov A G , Zyuzin A M
Published: November 2019

In the present work, the calculation and experimental studies of the spin-wave resonance (SWR) spectra in two- and three-layer magnetic films with dissipative or mixed spin pinning mechanisms are carried out. The calculation showed that the SWR spectra for two-layer ferrite-garnet films have approximately twice the number of spin-wave (SW) modes compared to three-layer films on the same field interval, which is confirmed by experiment. An increase in the mismatch of the dispersion dependences is shown for perpendicular and parallel orientations for a three-layer film compared to a two-layer film. The SW-mode linewidth 2ΔHn
in three-layer films is approximately twice as wide in two-layer films for identical values of the wave number.
Technology features of creating InSb-based spin-valve
Authors: Tsvelikhovskaya V M , Viglin N A , Patrakov E I , Kamenskii I Y , Maksimova I K
Published: November 2019

Technological route is reported how to fabricate an InSb spin device for studying spin-transport phenomena in CPP geometry. The device, which consists of ferromagnetic CoFe layer and MgO tunnel barrier deposed on the n-InSb single-crystal substrate, was manufacturing by method of contact photolithography with lift-off technology of drawing transfer in the topological layers. The optimal methods for preparation of InSb substrate surface and photoresist exposure parameters are found by measuring the voltage between InSb and ferromagnetic probe (Hanle effect) that appears due to the spin polarization of electrons injected from ferromagnet into InSb.
Investigation of the magnetic and adsorption properties of a FexNi1-x monolayer film on nonmagnetic metal substrates
Authors: Mamonova M V , Prudnikova I A
Published: November 2019

The adsorption energy of FexNi1-x monolayer film on the W, Ag and Au nonmagnetic substrates at low Miller index orientations of its surface face is calculated by the variational method of the spin-density functional (SDFT), depending on the concentration of the alloy components and the coating parameter. The temperature effects of the mixing of adsorbate and substrate atoms and the inhomogeneous distribution of magnetization are taken into account. Comparison of the values of the adsorption energy as a function of the concentration of the alloy components calculated at θ = 1 T = 0K within the framework of the variational and first-principle (VASP) approaches is presented.
Electronic properties of WTe2 and MoTe2 single crystals
Authors: Domozhirova A N , Makhnev A A , Shreder E I , Naumov S V , Lukoyanov A V , Chistyakov V V , Huang J C A , Semiannikova A A , Korenistov P S , Marchenkov V V
Published: November 2019

WTe2 and MoTe2 single crystals were grown, and their electrical resistivity in the temperature range from 80 K to 300 K, optical properties at room temperature in the spectral range of 0.17-5.0 eV were studied as well as theoretical calculations of the electronic structure were performed. It is shown that the temperature dependence of the electrical resistivity of orthorhombic WTe2 has a metallic type with resistivity value of (0.5-1) mOhmcm, while hexagonal MoTe2 has a semiconductor one and resistivity value (0.5-1) Ohmcm, which is three orders of magnitude larger than the resistivity of WTe2. Optical properties indicated that there is no contribution from free carriers in the entire spectral range studied. The calculated densities of the electronic states of MoTe2 and WTe2 showed the presence of a bunch of the molybdenum and tungsten electronic states in a wide energy interval with strong admixing of tellurium states. In the WTe2 compound, the larger number of the electronic states is located near the Fermi energy, characterizing a more metallic state in this compound as compared to MoTe2.
Spin current polarization and electrical conductivity in metal helimagnets
Authors: Ustinov V , Bebenin N , Yasyulevich I
Published: November 2019

The peculiarities of spin and charge kinetics in helical magnetic metals that are due to forces acting on the magnetic moment of conduction electrons in inhomogeneous magnetic field have been considered. Analyzing the equations of motion for non-equilibrium spin density shows that an electric field directed along the axis of the helix produces conduction-electron spin polarization along this direction. Under the same conditions, the directions of polarization of the spin current and polarization of the locally equilibrium spin density are collinear. The specific structure of the effective exchange field acting on the conduction electrons in helical magnets causes two additional spin relaxation mechanisms to emerge. In addition to the mechanism of spin-lattice relaxation, “diffusion” and “precession” mechanisms of spin relaxation exist in conductive helical magnets. The diffusion mechanism is analogous to the Dyakonov-Perel spin relaxation mechanism. The key point is that the inhomogeneities of a magnetic field initiate a coupling between the spin and charge systems. It has been shown that, in a helical metal, the electrical conductivity decreases due to the action of the non-uniform exchange magnetic field.
Magnetic and dielectric properties of composites based on magnetic microspheres
Authors: Vyzulin S A , Buz’ko V Y , Kalikintseva D A , Goryachko A I , Sarin L I , Kolantsov O A , Syr’ev N E
Published: November 2019

Composites with a filler based on a magnetic material ECOM-P and paraffin were investigated. The microstructure of the magnetic material was studied, the average particle size was determined. The influence of the concentration of magnetic filler on the scattering characteristics of electromagnetic waves in the frequency range from 15 MHz to 7 GHz is determined. The values of permittivity and permeability at frequencies of 1, 2 and 3 GHz are calculated.
Selection of rotating entrance window and target parameters for a gas-filled separator operating at high intensive heavy ion beams
Authors: Ibadullayev D
Published: November 2019

The durability of the targets and entrance window foils of the Dubna gas-filled recoil separator working at high intensive heavy ion beams was considered. The temperature, as a factor determining their durability, was calculated as a function of time in the conditions of their pulsed heating by heavy ion beam, followed by radiative cooling by radiation emitted from their surfaces. The temperatures were calculated for 48Ca heavy ion beam with intensity expected for the DC-280 accelerator. With the temperature calculated as a function of time, optimal parameters of the entrance window and target operation were chosen.
Prospects for the study of the strangeness and hypernuclei production at NICA/MPD
Authors: Zinchenko A , Kolesnikov V , Mudrokh A , Vasendina V , Voronyuk V
Published: November 2019

The prospects for the study of the strangeness and hypenuclei production with the MultiPurpose Detector (MPD) at NICA are presented and the detector performance for such physics analyses, evaluated from the Monte Carlo simulation, are demonstrated.
Exploring hot QCD matter via direct photons at ALICE
Authors: Peresunko D.
Published: November 2019

We review ALICE results on direct photon production in pp, pA and AA collisions and compare them to predictions of NLO pQCD calculations, hydrodynamic, and transport models. In pp and pA collisions the measured direct photon yield is consistent with NLO pQCD calculations, scaled with the number of binary collisions. In Pb-Pb collisions an additional direct photon contribution is observed at low pT
< 4 GeV/c which can be interpreted as a thermal direct photon contribution. The measured yield is larger than predictions of hydrodynamic models, but still consistent with them within uncertainties. The elliptic collective flow of direct photons was measured in central and mid-central Pb–Pb collisions and compared with hydrodynamic model predictions.
Doubly heavy baryons from the theoretical point of view
Authors: Berezhnoy A V , Likhoded A K , Luchinsky A V
Published: November 2019

The theoretical analysis of production, lifetime, and decays of doubly heavy baryons is presented. The lifetime of

Ξ

c
c

+
+

baryon recently measured by the LHCb Collaboration is used to estimate the lifetimes of other doubly heavy baryons. The production and the possibility of observation of Ξ
bc
baryon at LHC are discussed.
Exotic hadrons in the decays of vector bottomonia
Authors: Baru V , Filin A , Hanhart C , Nefediev A , Wang Q
Published: November 2019

Line shapes of the Zb
(10610) and Zb
(10650) bottomonium-like exotic states produced in the decays of the vector bottomonium ϒ(10860) are analysed. A combined analysis of the existing experimental data in the elastic and inelastic decay channels of the ϒ(10860) is performed within a nonperturbative coupled-channel approach which complies with the requirements of unitarity and analyticity of the multichannel amplitude. The nature of the Zb
states is revealed and the parameters of the interaction are extracted from the fit to the data.
Observation of the Higgs decay to beauty quarks
Authors: Noguchi Yohei
Published: November 2019

Higgs bosons decaying to b-quark pairs were searched in the production associated with vector bosons using 79.8 fb−1 data of pp collisions at the center of mass energy of 13 TeV provided by the Large Hadron Collider and recorded by the ATLAS detector. The observed (expected) significance of the signal is 4.9 (4.3) σ. This result was combined with the

H
→
b

b
¯

results of Run 1 and Run 2 datasets for vector boson fusion production and associated production with top quark pairs. A combination with H → γγ and 4ℓ decay modes in associated production with vector bosons was performed using the Run 2 results. The observed (expected) significance of this production modes is 5.3 (4.8) σ.
The background simulation of experiment for searching of 2v2K capture in 124Xe
Authors: Kazalov V V , Gangapshev A M , Gavrilyuk Yu M , Kuzminov V V , Panasenko S I , Petrenko O D , Ratkevich S S , Tekueva D A
Published: November 2019

We describe the Monte Carlo (MC) simulation package of the “2K-CAPTURE” setup and discuss the agreement of its output with data. The “2K-CAPTURE” MC simulates the energy loss of particles in detector and components of the passive shield and generates the resulting response in working volume large proportional counter (LPC). The simulation accounts for absorption, reemission, and scattering of both photons and neutrons and tracks them until they either are absorbed. The algorithm proceeds with a detailed simulation of the electronics chain. The MC is tuned using data collected with radioactive calibration source deployed in the internal channel of the installation. The simulation reproduces the energy response of the detector corresponding to distribution of the generated pointwise clusters of a charge of primary ionization in LPC.
Statistical data analysis in the DANSS experiment
Authors: Skrobova Nataliya
Published: November 2019

DANSS is a one cubic meter highly segmented solid scintillator detector. It is placed under a 3.1 GW industrial reactor at the Kalinin NPP (Russia) on a movable platform. The distance from the reactor core center is varied from 10.7 m to 12.7 m on-line. The inverse beta decay (IBD) process is used to detect antineutrinos. DANSS detects about 5000 IBD events per day.Sterile neutrinos are searched for assuming a 4 neutrino model (3 active and 1 sterile neutrino). The exclusion area in the sterile neutrino parameter plane is obtained using a ratio of positron energy spectra collected at different distances. Therefore, results do not depend on the shape and normalization of the reactor

v
˜

e

spectrum, as well as on the detector efficiency. The excluded area covers a wide range of the sterile neutrino parameters up to sin2 2θ
14 < 0.01 in the most sensitive region. The Reactor Antineutrino Anomaly optimum point is excluded with a confidence level higher than 5σ. A Gaussian CL
s
method was used to obtain exclusion areas. CL
s
method includes a point from sin2 2θ, Δm
2 plane into exclusion area only if the experiment sensitivity to such point is good. Details of this approach are presented.
The DAMPE experiment and its latest results
Authors: Fusco Piergiorgio
Published: November 2019

The DArk Matter Particle Explorer (DAMPE) is a high-performance space particle detector launched in orbit on 17 December 2015 by a collaboration of Chinese, Italian and Swiss scientific institutions, coordinated by the Chinese Academy of Sciences. It consists of a high-resolution segmented BGO electromagnetic calorimeter with a depth of 32 radiation lengths, a silicon-tungsten tracker-converter that reaches an angular resolution below 0.2°, an anti-coincidence shield and ion detector made of segmented plastic scintillators and a neutron detector made of boron-doped plastic scintillators. An overview of the experiment and a summary of the latest results coming from the observation of cosmic rays up to 100 TeV, of gamma-rays up to 10 TeV and of cosmic electrons up to 5 TeV is presented.
Hyperfine structure of S-states in muonic ions of lithium, beryllium and boron
Authors: Dorokhov A E , Martynenko A P , Martynenko F A , Sukhorukova O S
Published: November 2019

On the basis of quasipotential method in quantum electrodynamics we make precise calculation of hyperfine structure of S-states in muonic ions of lithium, beryllium and boron. Nuclear structure and recoil corrections of orders α
1 and α
6, vacuum polarization corrections in first and second orders of perturbation theory are taken into account. Total values of hyperfine splittings are obtained which can be used for a comparison with future experimental data.
Studies of the Electromagnetic Calorimeter with projective geometry for the MPD/NICA
Authors: Dabrowska B. , Krechetov Yu. , Kulikov V. , Martemianov M. , Tyapkin I. , Zinchenko A.
Published: November 2019

A projective geometry description of the MPD Electromagnetic Calorimeter (ECal) has been developed and implemented within the MpdRoot software framework. Using this package, characteristics of the detector were studied by Monte Carlo methods. Information about energy and spatial resolution as well as registration efficiency was obtained for different clustering procedures. One module of the detector, developed at JINR, was tested using electron beam at DESY. Energy scan for this prototype was carried out to estimate detector linearity. Results of the simulations and beam tests are presented.

A post-publication change was made to this article on 16 Mar 2020 to correct an author name and add a funding acknowledgement.
The Silicon Tracking System of the CBM Experiment at FAIR
Authors: Lavrik E
Published: November 2019

The Compressed Baryonic Matter (CBM) experiment at the future Facility for Antiproton and Ion Research (FAIR) aims to study the properties of nuclear matter at high net-baryon densities and moderate temperatures.

The Silicon Tracking System (STS) is the key detector to reconstruct with a high efficiency up to 1000 charged particle trajectories created in heavy-ion collisions at interaction rates of up to 10 MHz. It will determine the momentum of the particles with a momentum resolution Δp/p ≈ 1-2% which requires ultra-low detector material budget of 0.3-1% X0 per layer. The detector comprise eight layers of double-sided silicon micro-strip sensors and will be placed inside the 1 Tm superconducting magnet which limits the space available, which in turn requires advanced cooling approaches and mechanical design with precise tracking layers alignment. The micro-strip sensors have to be radiation hard and checked for their quality optically and electrically before the assembly.

This contribution gives an overview of the STS and presents the status of its component quality control and assembly procedures.
Track based alignment procedure for the CBM silicon tracking detector
Authors: Das Susovan , Schmidt Hans Rudolf
Published: November 2019

The CBM (Compressed Baryonic Matter) experiment at FAIR is being designed for the study of the QCD phase diagram in the region of the high baryon chemical potential at relatively moderate temperatures. The Silicon Tracking System (STS) is the central detector for momentum reconstruction of the produced charged particles in the CBM experiment. It consists of 8 layers of altogether ∼ 900 double sided silicon micro strip sensors. Limited mechanical precision(> 100μm) during the mounting, temperature differences during the experiment, influence of the applied magnetic field result in misalignment to the detector component positions. Therefore, the intrinsic spatial resolution(∼ 20μm) of the detector components has to be recovered by a track based alignment method. In this conference paper, the current status of implementation of the alignment algorithm is presented. For this work, the GBL (General broken line) track refit model is employed to create the necessary input data structure to provide the input to the standalone PEDE part of the χ2 minimization based MILLEPEDE II alignment algorithm.
Development of Transition Radiation Detectors for hadron identification at TeV energy scale
Authors: Belyaev N , Cherry M L , Dachs F , Doronin S A , Filippov K , Fusco P , Gargano F , Konovalov S , Loparco F , Mascagna V , Mazziotta M N , Ponomarenko D , Prest M , Pyatiizbyantseva D , Rembser C , Romaniouk A , Savchenko A A , Schioppa E J , Sergeeva D Yu , Shulga E , Smirnov S , Smirnov Yu , Soldani M , Spinelli P , Strikhanov M , Teterin P , Tikhomirov V , Tishchenko A A , Vallazza E , Vorobev K , Zhukov K
Published: November 2019

Many modern and future accelerator and cosmic ray experiments require identification of particles with Lorentz γ-factor up to 104 and above. The only technique which reaches this range of Lorentz factors is based on the transition radiation detectors (TRD). This paper describes the development of a TRD based on straw proportional tubes. A prototype of such kind of detector was built and tested at the CERN SPS accelerator. Monte Carlo simulation model of the detector which matches well the experimental data was developed. This program was used for the simulation of a full-scale TRD for hadron identification at TeV energy scale.
A quasi-monochromatic electron beam of the accelerator “Pakhra” for calibration of detectors
Authors: Alekseev V I , Baskov V A , Dronov V A , L’vov A I , Koltsov A V , Krechetov Yu F , Malinovsky E I , Pavlyuchenko L N , Polyanskiy V V , Sidorin S S
Published: November 2019

Characteristics of the calibration quasi-monochromatic beam of secondary electrons of the accelerator “Pakhra” of the P N Lebedev Physical Institute of the Russian Academy of Sciences based on the magnet SP-57 are presented. The energy resolution of the beam from a copper converter in the thickness range of 0.1-5 mm and the interpolar gap in the magnet 6 cm amounted to δ = 10−4.5 % in the energy range of the electron beam E = 98−294 MeV, respectively.
Investigations of SiPM based large scintillation detectors
Authors: Runtso M F , Arkhangelskaja I V , Arkhangelskiy A I , Chasovikov E N , Galper A M , Egorov A E , Leonov A A , Naumov P Yu , Naumov P P , Suchkov S I , Yurkin Y T , Topchiev N P
Published: November 2019

Different types of light concentration for large fast scintillation detectors with silicon photomutipliers as photosensors for the satellite based gamma-ray telescope GAMMA- 400 are analysed. Some proposals for their possible implementations are made.
The dynamics of ionization waves formation in a transverse nanosecond plasma-beam discharge with a slotted cathode in argon
Authors: Ashurbekov N A , Iminov K O , Zakaryaeva M Z , Ramazanov A R , Shakhsinov G Sh
Published: November 2019

The article presents the results of an experimental study and numerical simulation of the spatio-temporal dynamics of ionisation processes in the gap between the electrodes and inside the cathode cavity during the formation of a nanosecond discharge in argon at pressures in the chamber from 1 to 10 Torr. The correspondence between the density distribution of charged particles and the optical patterns of the discharge is established. A numerical simulation of the formation of a limited discharge in argon under various external conditions is constructed that accounts for the influence of the charge deposited on the surface of the dielectric wall, the coefficient of secondary emission of electrons from the cathode surface and the effect of the space charge on the distribution of electric potential between the electrodes. The role of the surface charge deposited on the dielectric walls in the formation of the spatial structure of the discharge is determined. The results of numerical simulation are compared with experimental data. It is shown that the electron concentration in a discharge limited by dielectric walls is an order of magnitude higher than in an unlimited discharge under the same external conditions. The general patterns of formation and development of a limited discharge in argon are discussed and the main physical processes affecting the dynamics of development and the spatial structure of the discharge are established.