bluuebunny/crossref_metadata_2025 huggingface dataset:
Template synthesis of different metal nanowires with applying of magnetic field
Authors: Cherkasov D , Doludenko I , Artemov V , Panov D , Zagorskiy D , Bedin S , Khaibulin R
Published: November 2019

This paper presents an investigation of electrodeposition of metal in pores of track etched membranes in presence of magnetic field. Where were obtained as homogeneous and heterogeneous nanowires. There is shown that magnetic field affects both on deposition process and on structure of metal nanowires. Particularly, samples obtained were investigated with help of methods of scanning electron microscopy, X-ray analysis and magnetometry.
Effect of temperature on the exchange bias in FeMn/X/Fe20Ni80 (X = Ta, Gd) films
Authors: Adanakova O A , Lepalovskij V N , Stepanova E A , Vas’kovskiy V O
Published: November 2019

The influence of temperature on the exchange bias in the Fe50Mn50/X/Fe20Ni80 (X = Ta, Gd) films was investigated. It is shown that in the film structures without a spacer between FeMn and permalloy layers, the temperature dependence of the value of the exchange bias field is non-monotonous. The introduction of an ultrathin spacer leads not only to a change in the magnitude of the interlayer exchange coupling, but also to a change in the behavior of its temperature dependence.
Magnetic and resonance properties of exchange spring multilayers [(CoP)soft/NiP/(CoP)hard]n
Authors: Shiyan Ya G , Patrin G S , Patrin K G , Furdyk V P
Published: November 2019

The magnetic resonance properties of [(CoP)soft/NiP/(CoP)hard/NiP]n exchange-spring multilayer films with a thickness of a nonmagnetic layer 4 nm have been experimentally studied in comparison to data for 2 nm thickness. A noncollinear three-sublattice magnetic structure assumed to be realized similar to the case of 2 nm NiF-layer thickness. The increase in the number of blocks n in the multilayer structure leads to the appearance of the third absorption peak, however, its intensity tends to zero at n → 20.
Identification of defects in a ferromagnet by solving the inverse problem of magnetostatics
Authors: Nikitin A V , Gobov Yu L
Published: November 2019

For many industries, the problem of detecting and classifying surface defects by a magnetic method is very important. Wherein the mutual configuration of magnetic converters and the object under study can be shown on the example of a device for in-pipe inspection of large-diameter pipes of gas pipelines. In this case, the magnetic transducers are located in the device inside the pipe, while the defects are located on the outer surface of the pipe. The data obtained from magnetic Hall transducers, measuring the magnetic field of scattering over the entire surface of the pipe, allows us to solve the inverse problem of magnetostatics on the restoration of magnetic fields to their sources. Due to the fact, that the pipes are made of a magnetically soft ferromagnet, it becomes possible to solve the problem of restoring the geometry of the surface corrosion defect in the metal. The proposed work contains an algorithm for reconstructing the geometry of surface defects of corrosion of an arbitrary shape from the measured magnetic scattering field over the metal surface opposite to surface, which contained the defect.
Main features of distributions of the magnetic flux leakage fields of defects different shapes
Authors: Novoslugina A P , Smorodinskii Ya G
Published: November 2019

The features of topography of the magnetic fields of various defects are considered using the finite element method (FEM). The distinctive attributes of these defects are identified and some recommendations are given on determining different types of defects. It is shown that extremes of the normal component of the magnetic field created by defects are closely connected with an orientation and an angle of inclination of a defect in a plate. An approach for estimating this angle of inclination of surface defects and extended subsurface defects is proposed.
Synthesis and functional characterization of poly(p-xylylene)-MnSb nanocomposite films
Authors: Oveshnikov L N , Zav’yalov S A , Streltsov D R , Chumakov N K , Trunkin I N , Nesmelov A A , Chvalun S N
Published: November 2019

In this study, structure and magnetic properties of poly(p-xylylene)-MnSb nanocomposite films with different inorganic filler content were investigated. The thickness of all studied films was about 200-300 nm as determined by scanning electron microscopy. It was found that the filler concentration strongly affects surface morphology of the composite films. AFM revealed that the film with the lowest MnSb content has globular surface mophology, presumably formed by polymeric grains with small MnSb nanoparticles on their surface. Ferromagnetic hysteresis loop was observed for all studied films at room temperature with the saturation magnetization values correlating with the MnSb content.
Two different types of ferromagnetic state in TiO2-Co nanopowders
Authors: Uimin M A , Privalova D V , Volegov A S , Minin A S , Konev A S , Yermakov A Ye , Gaviko V S
Published: November 2019

TiO2-Co nanopowders were synthesized by the sol-gel method and gas condensation method. The structure of powders and its change during various heat treatments in air and hydrogen was investigated. The samples obtained by the gas condensation method contain ferromagnetic regions in the as-prepared state. This ferromagnetism does not disappear when annealed in air at 773 K. The magnetization curves of these powders are measured in the temperature range from 2 up to 773 K and the temperature dependence of the ferromagnetic contribution is analyzed.
Observation of the inverse magnetoelectric effect in PZT/FeCuNbSiB two-layered composite structures
Authors: Efremova S L , Shalygina E E , Shalygin A N
Published: November 2019

In recent years, much attention has been paid to the study of magnetoelectric (ME) effects in solids, which was caused by their potential practical applications. Of particular interest are composite multiferroic materials containing ferroelectric and ferromagnetic phases, since significant ME responses may occur in them. This paper is devoted to the study of the inverse ME effect in a two-layered composite sample consisting of a piezoelectric Pb(Zr, Ti)O3(PZT) plate and an amorphous FeCuNbSiB ferromagnetic ribbon. It was found that the inverse ME effect depends on the magnitudes of the external magnetic fieldH, the electric voltageUand on the mutual orientation ofHandU.
Remanence magnetization of iron oxide particles with different size distribution
Authors: Dikansky Yu I , Ispiryan A G , Kunikin S A
Published: November 2019

Remanent magnetization curves for two samples of iron oxide particles with different size distributions were investigated. It was observed that the isothermal remanent magnetization curve and the DC demagnetization remanence curves are strongly depended on fine particle size. Moreover, it was figured out that remanent curves are quite complicated for the assembly of larger particles. In terms of remanence dependence analysis, it was shown that favourable interaction mechanism for the assembly of iron oxide particles strongly depends on particle size. The isothermal remanent magnetization curves were analysed in terms of the Stoner-Wohlfarth model. It leads to determine particle anisotropy field. It was found that the anisotropy field depends on particle size. It was assumed that observed differences related to different magnetic structure of particles.
Magnetostriction in ferrogels based on physical and chemical networking with embedded strontium hexaferrite particles
Authors: Safronov A P , Mikhnevich E A
Published: November 2019

Magnetostriction of ferrogels based on physical and chemical networking with embedded strontium hexaferrite particles was studied in 420 mT uniform magnetic field. Ferrogel with physical networking was based on natural polysaccharide – guar gum, which gelates due to formation of H-bonds. Ferrogel with chemical networking was synthesized by radical polymerization of acrylamide. Magnetostriction of the physical ferrogel resulted in the increase of length of the gel specimen along the field lines and in the proportional decrease of its width in the direction across the field lines. In case of chemical ferrogel, both the length and the width increased in the uniform magnetic field leading to the increase of the ferrogel volume.
Magnetic properties of R(Co0.88Fe0.12)2 quasi-binary compounds
Authors: Anikin M S , Tarasov E N , Kudrevatykh N V , Volegov A S , Zinin A V
Published: November 2019

In this paper the results of magnetic properties study for a series samples of R(Co0.88Fe0.12)2 type intermetallic compounds with a heavy rare-earth elements (R = Gd, Tb, Dy, Ho, Er) are presented. Such materials having a plateau-like temperature dependences of magnetic entropy change in the temperature range lower Curie point are considered as a promising functional materials for magnetic refrigerators. Their phase composition was controlled by X-ray diffraction analysis with a help of Bruker D8 Advance diffractometer. Magnetic field magnetization dependences – M(H) were measured using a SQUID magnetometer (MPMS-XL-7, Quantum Design) within the temperature range of 5 – 600 K in magnetic fields up to 5600 kA/m. The crystal lattice parameter – a, Curie temperature – TC
, coercivity – Hc
and residual magnetization – Mr
values are analyzed as a functions of R-element atomic number. For compounds with Tb, Dy, Ho and Er the second picks on the high field susceptibility temperature dependences – χhf
(T) were found in the temperature range lower their TC.
Electronic properties and X-ray absorption spectra of Ba1-xKxBiO3
Authors: Zhumagulov Yaroslav , Krasavin Andrey , Lukyanov Alexander , Neverov Vyacheslav , Yaroslavtsev Alexander , Menushenkov Alexey
Published: November 2019

The band structure, the density of states, and X-ray absorption spectra of the oxygen K-edge for perovskite high-temperature superconductors based on BaBiO3 are calculated by the density functional theory method for different levels of potassium doping in the ground and optically excited states. It is shown that changes in the properties of the electronic subsystem near the Fermi level can be correctly described by taking into account local structural inhomogeneities caused by doping and exposure to optical radiation. The appearance with doping of hole carriers on the hybridized Bi6s – O2p
σ* orbital is demonstrated, which agrees with the model of the electronic structure of bismuthate high-temperature superconductors based on a spatially separated Fermi-Bose mixture.
The dynamic processes in second generation HTS tapes under the pulsed current and magnetic impact
Authors: Anischenko I V , Pokrovskii S V , Rudnev I A
Published: November 2019

This paper presents the results of complex multiphysical modelling of non-equilibrium states arising in high-temperature superconducting composites under current, magnetic, and combined control switching impacts types. The simulation and analysis of the dynamics of electrophysical and thermal processes occurring in the HTS composites layered structure taking into account the influence of local thermal processes in the composite structure, in particular, heat generation bursts during a pulse, has been performed. The HTS composite switching times from the superconducting to the normal state have been investigated for various current pulses amplitudes in homogeneous magnetic fields. An experimental verification of the numerical model has been carried out.
Superparamagnetic nanopreparations in early diagnostics and treatment of cancer
Authors: Brusentsov N A , Polyanskiy VA , Golubeva I S , Baryshnikova M A , Barmashov A E , Bukreyev Yu M , Bocharova O A , Gulyayev M V , Pirogov Yu A , Anisimov N V
Published: November 2019

The superparamagnetic nanoparticles of magnetite citrate (SNMCs) consisting of nanospheres aggregates with the hydrodynamic diameter being between 15 to 35 nm with a magnetite core diameter of 3 to 12 nm, coated with of citrate anions was synthesized. A water 2-5% sol of SNMC was successfully tested as magnetic resonance imaging (MRI) contrast agent. The same 40% sol was then combined with Inox and used at regional magneto-thermo-chemo-therapy (RMTCT) of Lewis lung carcinoma (LLC) and Ehrlich carcinoma (EC), in female C57Bl / 6j mice. In the early stages of carcinoma development, the proliferation centers of LLC and EC cells were visualized and, during treatment, they obtained a significant increase in the efficiency of regional magneto-thermo-chemo-therapy.
Design magnetic matrices for cell technology supporting devices
Authors: Volchkov S O , Melnikov G Y , Blyakhman F A , Kurlyandskaya G V
Published: November 2019

Biomedical applications of magnetic materials are a hot topic of present day research. Special attention is paid for design and development of appropriate instrumentation. In this work magnetic system consisting of an equidistant set of commercial permanent magnets (6 × 4 assay) was proposed, designed and tested for further employment in the experiments in cell cultivation experiments. Magnetic field distribution was experimentally measured in 3 axes: OX, OY, OZ by gaussmeter. The results were statistically analyzed. Constant magnetic field near the center of XY plane was relatively homogeneous but at edges significant value of magnetic field gradient was observed. With increasing of Z distance, the decreasing of magnetic field strength was observed. Obtained parameters of a designed system are satisfactory and therefore it can be recommended for cell cultivation experiments when application of external magnetic field is desired.
Changes in morphotype in the population of E.coli in the presence of metal containing nanoparticles
Authors: Denisova T P , Simonova E V , Kokorina L A , Maximova E N , Safronov A P , Rommel M V , Kurlyandskaya G V
Published: November 2019

The level of variability of the E.coli morphotype under the influence of iron oxide nanoparticles (MNPs) depending on their concentration was studied as well as the adaptive capabilities of the microbial population under growth conditions was evaluated.The presence of γ-Fe2O3 nanoparticles in the cultivation fluid affects the cultural and morphological properties of the microbial population of E.coli in the process of its development. The appearance of new morphotypes of colonies and cells can be considered as a manifestation of an adaptive mechanism. A change in the morphology of the microbial cell with a high concentration of MNPs leads to abnormal growth and disruption of the division process.
GdFe2 Laves phase intermetallic system under pressure: an ab-initio study
Authors: Kokorina E E , Medvedev M V , Nekrasov I A
Published: November 2019

Here we perform abinitio study of Curie temperature TC
under hydrostatic pressure for intermetallic compound GdFe2. To calculate TC
for GdFe2 we applied mean-field solution of the Heisenberg model for several magnetic sublattices with DFT/LDA calculated values of necessary exchange interaction integrals and local magnetic moments. To compare with available experimental data pressure values were taken from zero up to about 70 Kbar. It corresponds to 2% compression of the volume of the unit cell. In agreement with experimental data
TC grows under pressure. It was shown that Fe ions magnetic sublattice alone provides only about 75% of the experimental Curie temperature TC
exp. Gd sublattice is found to give very weak contribution to the TC
exp. Here we show that the missing 25 % of TC
exp
comes from Fe-Gd exchange pairs.
Investigation of magnetocaloric effect: Stoner approximation vs DMFT
Authors: Igoshev P A , Nekrasov I A , Pavlov N S , Chinyaev T H , Yakupov E O
Published: November 2019

A comparative study of the magnetocaloric effect (MCE) in metals within the single-band Hubbard model on the face-centered cubic (fcc) lattice using both mean-field (Stoner) approximation (MFA) and dynamical mean-field theory (DMFT) is done. The MCE is investigated in the case of second order magnetic phase transition from ferromagnet to paramagnet. To ensure presence of itinerant ferromagnetism in the Hubbard model the special case of spectrum parameters generating giant van Hove singularity at the bottom of the band is considered, while the Fermi levelEfis in the vinicity of the band bottom. To compare MCE within MFA and DMFT temperature dependence of magnetization, total energy and finally entropy for a set of Coulomb interactionsUat zero and finite values of magnetic fieldhfor both methods were performed. Also one of the MCE potentials, isothermal entropy change, as a function of temperature ∆S(T)for both MFA and DMFT is calculated. In the MFA, the expected maximum value of ∆S(T)at the Curie temperatureTC(∆Smax) quite significantly decreases whileUgrows. Similar but much weaker decreasing of ∆Smaxis found for DMFT results. The account of local quantum fluctuations results in larger values of ∆Smaxwithin DMFT than within MFA. A peak width of ∆S(T)at half height is approximately the same for both methods. Another effect of DMFT local quantum fluctuations is the destruction of anomalous Curie temperatureTCdependence onUpresent in MFA, which is invoked by an effect of giant van Hove singularity. However the relative cooling power (RCP) is very close in DMFT and MFA for the same model parameters and goes down uponUincrease.
Ab initio study of DyFe4Ge2 alloy
Authors: Matyunina M V , Zagrebin M A , Sokolovskiy V V , Buchelnikov V D
Published: November 2019

Using density functional theory, the magnetic and electronic properties for DyFe4Ge2 alloy with four different structures were studied. The exchange-correlation effects were treated by the two approximations: local density approximation (LDA) and LDA+U. It is shown, that for all considered structures both approximations give rise to similar results for magnetic moments and partial densities of states for Fe (Ge) atoms. The DOS calculations for Dy atoms demonstrated significant difference between LDA and LDA+U results. The strongest antiferromagnetic and ferromagnetic interactions were found for iron atoms located on regular sublattices in orthorhombic structures.
Magnetocaloric effect in the 2D dilute Ising system
Authors: Shadrin A V , Ulitko V A , Panov Y D
Published: November 2019

We consider the magnetocaloric effect (MCE) for the 2D Ising system with a fixed concentration of non-magnetic mobile charged impurities. Pseudospin formalism and highperformance Monte Carlo simulations are used to describe the system and, in particular, to obtain the temperature dependences of the MCE parameters for our system. The effect of the impurityimpurity interaction strength on the concentration dependence of the MCE parameters is discussed, as well as the possibility of using the MCE effect to reveal a hidden frustration in the system.
Structural, magnetic and magnetocaloric properties of NdPrFe14B and its hydrides
Authors: Tereshina I , Kaminskaya T , Ivanov L , Politova G , Drulis H , Gorbunov D , Paukov M , Tereshina-Chitrova E , Andreev A
Published: November 2019

A systematic study of the influence of interstitial hydrogen on the structure, morphology of surface, magnetic and magnetothermal properties in multicomponent (Nd0.5Pr0.5)2Fe14BHx (x = 0; 2.7; 4.3) are reported. Partial substitution of Pr for Nd allows a decrease of the spin-reorientation transition temperature from 135 K for Nd2Fe14B to 73 K for (Nd0.5Pr0.5)2Fe14B. Hydrides (Nd0.5Pr0.5)2Fe14BHx crystallize in a tetragonal crystal structure (space group P42/mnm) of the Nd2Fe14B-type. Both lattice constants and unit cell volume increase upon hydrogen absorption. It was also found that the surface of the hydrogenated sample was very severely damaged by the introduction of hydrogen. Magnetic studies of both initial compound and the hydrides were performed on bulk and powder samples in static and pulsed magnetic fields up to 14 and 58 T, respectively. Hydrogenation has a significant effect on magnetic properties of a multicomponent alloy (Nd0.5Pr0.5)2Fe14B: Curie temperature and saturation magnetization increase, while temperature of SRT decreases (TSRT = 63 K for (Nd0.5Pr0.5)2Fe14BHx with x = 2.7 and 4.3). The magnetocaloric effect (MCE) in the range of spin-reorientation transition also decreases significantly. We analyzed magnetic properties of (Nd0.5Pr0.5)2Fe14BHx and compare them with that of Nd2Fe14BHx. Magnetic phase diagrams are constructed.
Low-temperature magnetostriction and distortions in the rare-earth Laves phases
Authors: Politova G , Ganin M , Kaminskaya T , Mikhailova A , Nacke B , Filimonov A , Burkhanov G
Published: November 2019

The effects of partial substitution of dysprosium in Tb0.2Dy0.8Co2 by terbium and gadolinium on the structure and magnetic properties have been studied. Two compositions, Tb0.3Dy0.7Co2 and Tb0.2Dy0.7Gd0.1Co2 have been synthesized. Their crystal structure, in contrast to the structure of the original compound, has both tetragonal distortions and rhombohedral distortions at lower temperatures. Anomalies of magnetostriction and magnetocaloric effect near the observed magnetic phase transitions have been studied. The sign-alternating temperature dependences of the longitudinal and transverse magnetostrictions associated with various types of crystal structure distortions of the alloys are revealed.
Effect of lattice vibrations on magnetic properties of metals at finite temperatures
Authors: Melnikov N B , Paradezhenko G V , Reser B I
Published: November 2019

We investigate the effect of electron-phonon interaction in the dynamic spin-fluctuation theory of metallic magnetism. Electron-phonon interaction is represented by fluctuations of the crystal lattice potential. We illustrate the theoretical results in the example of Fe and Ni. We show that the effect of phonons on temperature dependence of magnetic characteristics is appreciable in Fe, but not as large as in the static single-site spin-fluctuation theory and spin dynamics using classical Hamiltonians. On the contrary, in Ni the effect of phonons is small in agreement with the results of the spin dynamics.
Hybrid states of Tamm plasmon polaritons in nanostructures with Bi-substituted iron garnets
Authors: Mikhailova T V , Lyashko S D , Tomilin S V , Shaposhnikov A N , Karavainikov A V , Berzhansky V N
Published: November 2019

The work presents the results of investigation of hybrid states of Tamm plasmon polaritons (TPP) in magnetoplasmonic nanostructures (MPNS) based on Bi-substituted iron garnet (Bi:IG) and Au layers and nanoparticles. To study the interaction of resonances, two MPNS were synthesized with gold-coated dielectric layer of gradient thickness. It was shown the difference in properties of model MPNS with hybrid state of TPP – Fabry-Perot and a single TPP excitation. It was suggested to use the hybrid state to increase the sensitivity of optical sensors.
Magnetization reversal in NiFe2O4/SrTiO3 nanoheterostructures grown by laser molecular beam epitaxy
Authors: Krichevtsov B , Gastev S , Mashkov K , Kaveev A , Korovin A , Lutsev L , Suturin S , Lobov I , Telegin A , Lomov A , Sokolov N
Published: November 2019

NiFe2O4/SrTiO3(001) nanoheterostructures have been fabricated by laser molecular beam epitaxy method. Surface morphology and crystal structure of Ni-ferrite films were analysed by atomic force microscopy (AFM), reflection of high energy electron diffraction (RHEED), X-ray diffraction (XRD). X-ray methods prove the presence of inverse spinel crystal structure of films that was confirmed by measurements of spectral dependence of optical polar Kerr (PMOKE) effect. Study of magnetization reversal for different orientations of magnetic field carried out by vibration sample magnetometry (VSM) and longitudinal magneto-optical Kerr effect (LMOKE) are presented. In-plane magnetization loops exhibit 90° period indicating presence of biaxial magnetic anisotropy. Asymmetry of LMOKE hysteresis loops is related to manifestation of quadratic in magnetization effects in reflection of light.
Strain-magneto-optics in ferrite-spinel – new magneto-optical phenomena associated with magnetoelastic interactions
Authors: Telegin A V , Sukhorukov Yu P , Bebenin N G
Published: November 2019

The correlation between magnetoreflection, magnetotransmission of unpolarized light in the infrared range and the magnetoelastic properties of magnetics is reported for the ferrimagnetic spinel CoFe2O4 single crystal. The new physical mechanism responsible for the spectral and field-dependent peculiarities of magnetoreflection and magnetotransmission in the ferrite-spinel possessing strong magnetostriction is discussed. The influence of a magnetic field on specular reflection and transmission spectrum is likely to be indirect: magnetic-field-induced strong strains and deformations of the crystal lattice lead to the change in the electron energy structure and, hence, optical properties of CoFe2O4. The revealed mechanism of new infrared magnetooptical effect in magnetostrictive magnetics paves the way towards new research area called as a strain-magneto-optics.
Strong changes in electronic transport and magnetic properties of Co2YSi Heusler alloys at Y-component variation
Authors: Perevozchikova Yu A , Semiannikova A A , Terentev P B , Eisterer M , Korenistov P S , Marchenkov V V
Published: November 2019

The Co2
YSi (Y = Ti, V, Cr, Mn, Fe, Co, Ni) Heusler alloys can manifest the properties of half-metallic ferromagnets. These compounds are promising materials for spintronics since almost 100 % spin polarization of charge carriers can be realized at room temperature. We measured the electroresistivity, magnetic and galvanomagnetic properties of the Co2
YSi (Y = Ti, V, Cr, Mn, Fe, Co, Ni) Heusler alloys from 4.2 K to 300 K and in magnetic fields up to 100 kOe. The type, concentration and mobility of charge carriers were estimated. The Y-component variation in the Co2
YSi Heusler alloys is found to affect strongly the number of current carriers and alter the electronic band structure near the Fermi level E
F and, consequently, the electronic transport and magnetic properties of the Co2
YSi (Y = Ti, V, Cr, Mn, Fe, Co, Ni) Heusler alloys.
Simulation of magneto-optical properties of nanocomposites (CoFeZr)x(Al2O3)1-x
Authors: Yurasov A , Yashin M , Ganshina E , Granovsky A , Garshin V , Semenova D , Mirzokulov Kh
Published: November 2019

The magnetooptical spectra of the transverse Kerr effect of (CoFeZr)x(Al2O3)1-x nanocomposites are calculated within the framework of the symmetrized Maxwell-Garnett (SMG) approximation. The quasi-classical size effect and the size distribution of the granules were taken into account. The calculation results for the spectral range 0.5-3.5 eV and different concentrations of the magnetic component are in semi-quantitative agreement with the experimental data. A possible reason for the existing discrepancy is the difference between the optical and magneto-optical parameters of ferromagnetic granules from those corresponding for bulk samples.
Influence of solution acidity on growth kinetics, structure and magnetic properties of Co-P films, obtained by chemical deposition
Authors: Chzhan A V , Podorozhnyak S A , Patrin G S , Rudenko R Yu , Onufrienok V V
Published: November 2019

The results of studies of the effect of solution acidity on the growth kinetics, structure and magnetic properties of Co-P films obtained by chemical deposition are presented. It was shown that the growth of Co-P films in the low pH region occurs mainly due to the growth of crystallite sizes, and in the high pH region, due to an increase in the nucleation rate. From the analysis of the chemical equilibrium of redox reactions, taking into account the balance of citrate and hydroxyl complexes of Co, a qualitative explanation of the features of the change in the rate and nature of the deposition of Co atoms from pH is proposed.
Structure and magnetic properties of melt-spun ribbons of Sm(Co,Fe,Cu,Zr)z with high cobalt content
Authors: Khudina E V , Zheleznyi M V , Minkova I O , Rybin P S , Menushenkov V P
Published: November 2019

In this work the investigation of structure and magnetic properties of SmCo7.5Fe3.09Cu0.84Zr0.3 and SmCo7.52Fe3.01Cu0.84Zr0.28 melt-spun ribbons with high cobalt content after different heat treatments was performed. The phase composition and magnetic properties of the samples were determined. Isothermal aging at 600-800 °C with subsequent slow cooling leads to the slight increase in coercivity of the samples. After arc-melting the phase composition of the samples is hexagonal Sm2Co17 and CoFe. After melt-spinning a small amount of the disordered SmCo7 phase is detected. After aging metastable SmCo7 disappears, and the phase structure is basically hexagonal phase Sm2Co17 and CoFe, except a tiny amount of SmCo5 and rhombohedral Sm2Co17 after aging at 800 °C. Magnetic properties of the samples are relatively low because the phases, essential for the high-coercive state in these alloys, do not form during applied heat treatments.
Negative anisotropy in Fe10Ni90 films
Authors: Savin P A , Adanakova O A , Lepalovskij V N , Kudyukov E V , Polozov K V , Vas’kovskiy V O
Published: November 2019

It is shown that in the Fe10Ni90 film the easy magnetization axis can be formed not along the deposition field, as it occurs in the Fe19Ni81 film, but across, that is a “negative anisotropy” effect occurs. A model that qualitatively describes this effect is proposed. Using the Kerr magnetometer, local measurements of the variation of the direction of the easy magnetization axis over the area of the film sample Fe10Ni90 were carried out and compared with the general view of the domain structure.
Magnetic properties of the GdFeSi – GdTiSi solid solutions
Authors: Kuchin A G , Platonov S P , Gaviko V S , Yakovleva M Yu
Published: November 2019

The GdFe1-x
Ti
x
Si, x=0-0.2 intermetallic compounds with a tetragonal crystal structure of the CeFeSi (P4/nmm)-type have been studied. It was obtained that the lattice parameter c and the Curie temperature increase quickly, whereas the lattice parameter a is almost unchanged in the system with increasing of Ti content. The GdFeSi compound is easily magnetized along the [001] axis, the field of magnetic anisotropy equals to ~3.8 kOe at T = 90 K. The saturation magnetization does not change in the GdFe1-x
Ti
x
Si system.
Magnetic properties of Sr2Ni1-xMgxMoO6 (x = 0.25 and 0.5) double perovskite structure
Authors: Urusova N V , Semkin M A , Filonova E A , Kratochvilova M , Neznakhin D S , Park J-G , Pirogov A N
Published: November 2019

Sr2Ni1-xMgxMoO6 (x = 0.25 and 0.5) double perovskites were synthesized by pyrolysis of glycerol–salt mixtures and their magnetic properties were investigated. X-ray diffraction was employed to refine crystal structures of these perovskite materials and set sample purity degree. The magnetic ground state of Sr2Ni1-xMgxMoO6 (x = 0.25 and 0.5) has been characterized using magnetic susceptibility measurements. They indicate that Sr2Ni0.75Mg0.25MoO6 is ordered in an antiferromagnetic state below 56 K while Sr2Ni0.5Mg0.5MoO6 is paramagnetic.
Features of the scattering of exchange spin waves by layer and superlattice of biaxial ferromagnets
Authors: Poimanov V D , Shavrov V G
Published: November 2019

The paper studies the scattering of exchange spin waves at the interface of biaxial magnetic materials with a uniform ground state and describes a method for finding the reflection and transmission coefficients from an isolated boundary, layer, and multilayer structure of such materials. The breaking of the axial symmetry of the precession of magnetization leads to the formation of surface exchange waves at the interface. These waves correspond to the imaginary roots of the characteristic equation and have the opposite to the bulk waves chirality of precession. Taking them into account aligns the number of boundary conditions and unknown amplitudes. The scattering coefficients are obtained by expanding over a small ellipticity parameter in the zero and first approximations. A comparison with the exact solution was made. It is shown that the frequency dependence of the reflection coefficient can be non-monotonic, and it can turn to zero, which corresponds to the equality of the wave impedances of the adjacent media.
63,65Cu NMR study of the antiferromagnet CuCrO2
Authors: Smolnikov A , Arapova I , Ogloblichev V , Piskunov Y , Sadykov A , Mikhalev K , Furukawa Y , Barilo S , Shiryaev S
Published: November 2019

The 63,65Cu NMR and NQR spectra have been obtained in single crystal sample of CuCrO2 in the magnetically ordered phase. The components of the electric field gradient tensor (EFG) characterizing the structure of the nearest environment of copper ions are determined from the analysis of the spectra. Comparative analysis obtained data with similar data of paramagnetic phase showed that the local charge environment of copper nuclei does not change during the magnetic phase transition.
Precession frequency and switching time of the magnetization vector of the spin-valve free layer with longitudinal anisotropy
Authors: Iusipova Iuliia A
Published: November 2019

In this paper, a magnetization vector dynamics of a spin-valve free layer with the planar anisotropy based on various materials was simulated. Two dynamics types were identified, being of practical interest for MRAM (switching) and STNO (stable precession). The range of current and field values, corresponding to these spin-valve operation modes, were obtained. The numerical calculations of the switching time shown that Co80Gd20 is the best material for a spin valve as a part of MRAM. As a result of calculating the precession frequency, it was concluded that the most suitable for fabrication of STNO ferromagnetic layers is the alloy Fe60Co20B20.
Self-organization in the unit sell of a single crystal spinel Li0.5Ga2.5O4 and self-distribution of magnetic ions of chromium Cr3+
Authors: Shapovalov Vladimir A , Shavrov Vladimir G , Koledov Victor V , Kamantsev Alexander P
Published: November 2019

Self-organization of twelve structurally and magnetically non-equivalent sites and self-distribution of magnetic ions of chromium over these sites at the minima of the crystal field potential in a unit cell of single crystal lithium-gallium spinel Li0.5Ga2.5O4 is considered. The form of the crystal field potential at the location of a magnetic ion is determined by the nearest neighbours. If the crystal symmetry is similar to the cubic one, structurally non-equivalent ion positions are formed. In this case, the compound contains the related number of magnetically non-equivalent positions of the magnetic ion that are found in the electron paramagnetic resonance spectra.
Calculation of the exchange integrals for Co1-xNix alloy by Korring-Kohn-Rostoker method
Authors: Budko Sergey N. , Mamonova Marina V.
Published: November 2019

In this work we investigate the cobalt-nickel alloy magnetic properties. Calculations of lattice constants for Co, Ni and Co1-x
Ni
x
alloy with different concentrations were performed with the VASP framework. Calculations of the exchange integrals were carried out using the SPR-KKR package (spin-polarized relativistic Korring-Kohn-Rostoker method). For pure ferromagnets, the Co exchange interaction is ferromagnetic. For Ni, the exchange interaction of the nearest neighbors also is ferromagnetic, but the exchange interaction of the next nearest neighbors has a very weak antiferromagnetic character. In the Co1-x
Ni
x
alloy, the exchange interaction of the nearest neighbors J

Ni–Co

1 and J

Co–Co

1 increases with increasing nickel concentration. The next nearest neighbors exchange interaction at a concentration of Ni x ≥ 0.5 has an antiferromagnetic character.
Local magnetic study for cluster-layered Fe/Cr nanostructures
Authors: Miyanaga T , Ikeda Y , Hasunuma Y , Ponomarev D , Grebennikov V , Babanov Y A
Published: November 2019

Local magnetic structures of cluster-layered Fe/Cr thin films are studied by X-ray magnetic circular dichroism (XMCD) and extended X-ray absorption fine structure (EXAFS). The magnetic moment of Fe atoms evaluated from XMCD for Al2O3/Cr(70Å)/[Fe(1.2Å )/Cr(10.5Å)]30/Cr(12Å), which shows the minimum point in the resistivity, decreases as the temperature increases and disappears around the temperature of the minimum resistivity. EXAFS shows the local structure of this film around Fe atoms is rather disordered and it can be related the fluctuation of magnetic structure estimated from the theoretical analysis of the temperature dependence of magnetic moments.
Macroscopic quantum coherent effects induced by electric current in dynamics of lanthanide based single molecule toroics
Authors: Plokhov D I , Zvezdin A K
Published: November 2019

The dynamics of a quantum system with a large toroidal moment under the influence of a time-dependent electric current coupled with the toroidal moment is considered. The possibility of observing the quasi-anyonic excitations, the Bloch type oscillations in the precession motion of the toroidal moment, the Stark-type resonances, and the tunnel transitions between different precession modes are discussed.
Magnetic ordering in Fe/X/Gd (X=Cr, Pd) superlattices
Authors: Makarova M , Antropov N , Kravtsov E , Proglyado V , Khaydukov Y , Ustinov V
Published: November 2019

We have studied the influence Cr and Pd spacers on structure and magnetic ordering in Fe/Gd superlattices. The insertion of Cr and Pd spacers in Fe/Gd has been found to cause structural changes in Gd layers. In particular, an additional fcc Gd phase appears in Fe/Cr/Gd along with the main hcp Gd phase, while there is amorphous Gd structure in Fe/Pd/Gd. By combining SQUID magnetometry and polarized neutron reflectometry we have shown that interlayer Fe-Gd exchange coupling through Pd spacers is much stronger than through Cr one.
Influence of diffuse interfaces on the magnetoresistance in trilayer magnetic structures
Authors: Mamonova Marina V. , Prudnikov Vladimir V. , Prudnikov Pavel V. , Samoshilova Anna A.
Published: November 2019

The numerical Monte Carlo study of influence of diffuse interfaces on the magnetoresistance in trilayer magnetic structures Co/Cu(100)/Co and Pt/Co/Cu(100)/Co/Pt is carried out. The calculations of temperature dependence of the CPP magnetoresistance are realized for structures with thickness of cobalt films N=11 monolayers for cases with sharp and diffuse interfaces. Comparison of results shows that diffuse interfaces lead to appreciable influence on the magnetoresistance in these nanostructures.
Microstructure and magnetoresistance of Co90Fe10/Cu and Co65Fe26Ni9/Cu multilayers
Authors: Milyaev M A , Naumova L I , Bannikova N S , Proglyado V V , Patrakov E I , Krinitsina T P , Ustinov V V
Published: November 2019

Investigations of the microstructure, magnetic and magnetotransport properties of the optimized [Co90Fe10/Cu]
n
and [Co65Fe26Ni9/Cu]
n
multilayers with n = 32 prepared by magnetron sputtering are performed. These nanostructures exhibit the magnetoresistance values 83 % and 36 % at room temperature, respectively. The article presents the results of the influence of Co65Fe26Ni9 alloy on the magnetoresistance values and crystal structure of multilayers. In the periodic part of the nanostructure [Co65Fe26Ni9/Cu]
n
based on CoFeNi ternary alloy, besides fcc the formation of a bcc phase in the continuous boundaries around crystallites is found.
Magnetoresistive properties of exchange biased spin valve caused by helical magnetic ordering in dysprosium layer
Authors: Ustinov V V , Milyaev M A , Zavornitsyn R S , Krinitsina T P , Proglyado V V , Naumova L I
Published: November 2019

Spin valves containing CoFe/Dy/CoFe nanostructure as a pinned layer were prepared by magnetron sputtering. Investigations of microstructure and magnetoresistive properties were performed. The magnetoresistive properties of the spin valve were used as the instrument to study the changes in magnetic state of the dysprosium layer. The existence of noncollinear magnetic ordering in dysprosium polycrystalline nanolayer was observed. The angle between the magnetic moments in a top and bottom part of the dysprosium layer was estimated.
Strong indication of true quaternary fission of 252Cf (sf)
Authors: Pyatkov Yu V , Kamanin D V , Tomas A V , Alexandrov A A , Alexandrova I A , Goryainova Z I , Malaza V , Kuznetsova E A , Strekalovsky A O , Strekalovsky O V , Zhuchko V E
Published: November 2019

In our previous publications we discussed possible physical scenario standing behind rectangular–like structures in the fission fragments mass-correlation distributions from 252Cf(sf). The rectangle is bounded by the known magic nuclei such as 68Ni, 84Se and others. The fission events aggregated in the rectangle show extremely low total kinetic energies. Previously only decay mode with two Ni clusters in the exit channel was discussed. A more complete analysis is presented which gives additional arguments in favour of true quaternary fission of 252Cf (sf).
Investigation of the interaction of ion beams and X-ray quanta with deuterated crystal structures at the HELIS facility
Authors: Dalkarov O D , Negodaev M A , Rusetskii A S , Chepurnov A S , Kirsanov M A , Kishin I A , Kubankin A S , Kudryashov I A , Selivanova D A
Published: November 2019

The results of studies of the interaction of ion beams and X-ray quanta with deuterated crystal structures at the HELIS facility (LPI) are presented. Results on research of DD-reactions in deuterated crystal structures at deuteron energies 10 - 25 keV show significant enhancement effect. It is shown that the effect of the beams of ions Ne+ and H+ at energies in the range of 10 - 25 keV and a beam of X-radiation of 20 - 30 keV for deuterated target leads to stimulation of DD-reaction. For the target of CVD-diamond it is showed that the orientation of the sample with respect to the deuteron beam affects the neutron yield. Targets (deuterated CVD diamond, palladium, zirconium and titanium) were irradiated with both ion beams and X-ray quanta using an X-ray tube with an energy of up to 30 keV. Analysis of X-ray fluorescence spectra from deuterated targets of CVD diamond and palladium revealed "additional" peaks that are not identified by any of the characteristic radiation lines. Their appearance cannot be connected with any known element, as well as with diffraction processes.
Total reaction cross sections of neutron-rich light nuclei measured by the COMBAS fragment-separator
Authors: Erdemchimeg B , Artukh A G , Davaa S , Hue B M , Isataev T , Klygin S A , Kononenko G A , Khuukhenkhuu G , Lukyanov S M , Mikhailova T I , Maslov V A , Mendibaev K , Sereda Yu M , Penionzhkevich Yu E , Vorontzov A N
Published: November 2019

Preliminary results of measurements of the total reaction cross sections σR for nuclei 4He, 6He, 8He, 7Li, 8Li, 9Li, 1Li, 11Be, 9Be, 10Be, 11Be, 12Be, 8B, 10B, 11B and 12B nuclei at energy range (10-50) A MeV with 28Si target is presented. The secondary beams of light nuclei were produced by bombardment of the 15N (50 A MeV) primary beam on Be target and separated by COMBAS fragment-separator. In dispersive focal plane a horizontal slit defined the momentum acceptance as 1% and a wedge degrader of 600 μm Al was installed. The Bρ of the second section of the fragment-separator was adjusted for measurements in energy range (10-45) A MeV. The strong absorption model reproduces the A-dependence of ψR, but not the detailed structure. We are comparing our experimental data with predictions of microscopic (dashed line) and strong absorption model, Glauber multiple scattering theory and preliminary results are obtained.
Neutron lifetime: experimental problem or anomaly?
Authors: Serebrov A. P.
Published: November 2019

The review of experimental measurements of neutron lifetime is presented. Latest measurements with gravitational trap (PNPI NRC KI) and magnetic trap (LANL, USA) confirmed the result obtained by PNPI group in 2005. The results of measurements performed using UCN storing method are in good agreement; however there is a significant discrepancy at 3.5σ (1% of decay probability) level with beam method experiment. That discrepancy is mentioned in scientific literature as "neutron anomaly". The possible sources of the discrepancy are discussed.
Dissociation of6,7Li nuclei in nuclear photographic emulsion
Authors: Mekhimar M , Ahamed Y , El-Sharkawy S , Hegab M K , Osman O M
Published: November 2019

Diffraction dissociation process of6Li at incident momentum 4.5 AGeV/c and7Li at incident momentum 3 AGeV/c, provided by the JINR Synchrophastron, were studied using the photographic emulsion technique. The two stable isotopes of6Li and7Li were treated as two weakly-bound systems composed of (4He+d) and (4He+t) cluster configurations, respectively. Along the track double scanning method was carried out in order to search for6,7Li interactions in emulsion( Em). For6Li-Em and7Li-Em about 1050 and 1015 events were recorded with mean free path 14.5±0.5 cm and 15.1±0.6 cm respectively. The measured angular distributions of the outgoing fragments were compared with that calculated theoretically and good agreement between the experimental and theoretical values is obtained. This agreement supported the presence of6,7Li nuclei in a cluster mode at high energy reactions.
Observation of cluster structure of fission fragments
Authors: Strekalovsky A O , Pyatkov Yu V , Kamanin D V , Alexandrov A A , Alexandrova I A , Goryainova Z I , Malaza V , Kuznetsova E A , Strekalovsky O V , Zhuchko V E
Published: November 2019

The manifestation of a new original effect appearing at crossing of the metal foils by fission fragments is reported. The effect takes place predominantly at front impacts. The obtained results suggest that a fragment from conventional binary fission is borne in shape-isomer state which looks like a di-nuclear system with magic core.
Clusterization in heavy cold nuclei
Authors: Pyatkov Yu V , Kamanin D V
Published: November 2019

A cluster is broadly understood to be an object which keeps its identity in a larger scale system. Manifestations of clustering can be revealed in very different size systems from exotic nuclei to galaxies. In our work we search for cluster effects in low energy fission of heavy nuclei. In the series of experiments carried out with the spectrometers based both on the gas filled (FOBOS spectrometer and its modifications) detectors and mosaics of solid-state detectors (setups at the beams of alpha-particles and deuterons, COMETA spectrometer) using the “missing mass” method and with the direct detection of three decay partners, we have discovered a new type of the ternary decay of heavy nuclei dubbed by us “collinear cluster tri-partition (CCT)”. The most interesting aspects of both the original methodic used and the physics of the effect observed are discussed in the presented report.
Spectroscopy of 7He in the reactions of stopped pion absorption by 12,14C nuclei
Authors: Chernyshev B , Gurov Yu , Lapushkin S , Karpukhin V , Sandukovsky V , Schurenkova T
Published: November 2019

The production of the 7He states was studied in the reactions of stopped pion absorption by carbon isotopes: 12C(π−, p4He)7He, 12C(π−, d3He)7He and 14C(π−, t4He)7He. Measurements were performed using two-arm multilayer semiconductor spectrometer. The ground and excited states were observed in all three reactions. Narrow (Γ < 2 M∍B) state with the high excitation energy ≈ 16 MeV was observed in the 14C(π−, t4He)7He reaction.
Anisotropic flow measured in Pb-Pb collisions with the NA49 and NA61/SHINE experiments at CERN SPS
Authors: Golosov Oleg , Klochkov Viktor , Kashirin Evgeny , Selyuzhenkov Ilya
Published: November 2019

Results are presented for directed flow v
1 of negatively charged pions measured relative to the spectator plane in Pb+Pb collisions at the beam energy 40A GeV recorded by the NA49 experiment at CERN. The measurements were performed as a function of rapidity and transverse momentum in two classes of collision centrality. The projectile spectator symmetry plane is estimated using the transverse segmentation of the forward hadron calorimeters. Analysis details related to event selection and particle identification are provided along with a description of the procedure used to apply corrections for the limited detection efficiency. Additionally a systematic study of effects due to detector non-uniformity on pion directed flow measurement is presented.