bluuebunny/crossref_metadata_2025_split huggingface dataset:
Untwisting of a soft ferrocholesteric liquid crystal by shear flow and magnetic field
Authors: Novikov Alexander , Makarov Dmitriy 
Published: November 2019

Abstract
We theoretically study the effect of a shear flow and a uniform magnetic field on the helical structure of a ferrocholesteric liquid crystal with the finite anchoring between the liquid-crystalline matrix and magnetic particles (soft ferrocholesteric). The axis of the ferrocholesteric helix is orthogonal to the plane of the shear flow and the magnetic field. We derive the integral expressions for the pitch of the helix and magnetization of ferrocholesteric depending on the anchoring energy, field influence parameter, strength and orientation angle of the magnetic field, flow gradient and reactive parameter. It is shown that the shear flow is able to magnetize a ferrocholesteric liquid crystal. An increase in the field influence parameter or gradient of the shear flow velocity leads to a decrease in the critical fields of the ferrocholesteric-ferronematic transition.
Investigation of magnetic emulsions in magnetic field by rotating test-tube method
Authors: Belykh S , Yerin C 
Published: November 2019

Abstract
The effect of diffraction scattering of light in a magnetic emulsion in a magnetic field in a rotating test-tube has been investigated. The non-linear dependence of the angle of deviation of the diffraction band on the rotation speed is established. An interpretation of the effect is proposed based on the balance of torques from the magnetic field and the drag force of the fluid. Agreement with the experiment is possible on the assumption of the destruction of the chains of magnetic emulsion microdroplets during rotation.
Influence of uniform magnetic field on elastic modulus in polyacrylamide ferrogels with embedded nickel nanoparticles
Authors: Mikhnevich E A , Chebotkova P D , Safronov A P , Kurlyandskaya G V 
Published: November 2019

Abstract
Polyacrylamide ferrogels with embedded nickel magnetic nanoparticles were synthesized by radical polymerization in water. The elastic modulus of ferrogels was measured under unidirectional compression in a uniform magnetic field with a strength of 0, 165, 220 and 275 Oe. With an increase in the content of nickel particles in ferrogel from 0 to 5.3% by weight, the elastic modulus in zero magnetic field increased by 60%. The application of magnetic field parallel to the direction of compression resulted in the increase of modulus, and if the field was applied perpendicular to the compression, the modulus tends to decrease. Such trends are in good agreement with the features of magnetostriction of a non-compressible uniformly magnetized sphere in a constant magnetic field.
Neutron reflectometry studies of Gd/Nb and Cu30Ni70/Nb superlattices
Authors: Khaydukov Y , Kravtsov E , Morari R , Lenk D , Mustafa L , Kim G , Trapp M , Zhaketov V , Proglyado V , Zrdavkov V , Nikitenko Y , Krug von Nidda H-A , Keller T , Steitz R , Tideks R , Sidorenko A , Ustinov V , Aksenov V , Keimer B 
Published: November 2019

Abstract
We performed a comparative study of magnetic proximity effects in [Gd(5nm)/Nb(25nm)]12 and [Cu30Ni70(6nm)/Nb(27nm)]12 superlattices of S/F type by means of transport measurements and neutron scattering. Transport measurements have shown that Gd/Nb and CuNi/Nb superlattices shows 3D and 2D type of superconductivity respectively. In the case of proximity coupled Gd/Nb superconductor the effective thickness of the superconducting region, 300nm is enough to expel significant amount of applied magnetic field which was detected by neutron scattering. In decoupled CuNi/Nb superlattice thickness of every superconducting layer is only 27nm which is not enough to expel applied magnetic field. Our study shows how neutron reflectometry can be applied to study proximity coupling in superconducting/ferromagnet heterostructures.
Magnetic properties of Chelyabinsk meteorite (15 February 2013) at high temperatures
Authors: Korolev A V , Kurmaev E Z 
Published: November 2019

Abstract
Magnetic properties of the Chelyabinsk meteorite were studied in a wide temperature range – up to ~ 1300 K. The analysis shows that the meteorite contains ferromagnetic inclusions of both Fe-Ni alloy and pure iron. It has visually been demonstrated that iron inclusions of the Chelyabinsk meteorite experience no β→γ structural phase transformation.
Formation and structure of Nb3Sn layers in bronze-processed superconductors under various intermediate heat treatments
Authors: Popova E N , Deryagina I L 
Published: November 2019

Abstract
Multifilamentary Nb3Sn-based superconducting wires are created and used for various superconducting magnetic systems such as thermonuclear reactors and future large accelerator projects. The crucial role in achieving high superconducting characteristics is played by the structure of Nb3Sn layers, which, in its turn, is determined by a number of factors, such as fabrication route, composition, annealing schedules, etc. In the present study the superconducting layers formation and structure have been studied by SEM and TEM after various regimes of intermediate heat treatments and two-staged diffusion annealing. Optimal heat treatment schedules for the formation of perfect nanocrystalline structure of Nb3Sn layers for an achievement of highest critical current densities have been revealed.
Microstructure and critical current of bulk MgB2 superconductor
Authors: Krinitsina T P , Kuznetsova E I , Blinova Y V , Degtyarev M V 
Published: November 2019

Abstract
The structure of bulk MgB2 specimens after cold deformation in Bridgeman anvils and “Toroid” chamber and following recovery annealings has been studied by scanning and transmission electron microscopy. It is demonstrated that in spite of the matrix phase grain coarsening by 5-7 times under annealing compared to the as-deformed state, the critical current density increases by a factor of 3 (6.7×104 A/cm2 at 30 K after deformation in the “Toroid” chamber and recovery annealing).
Application of NMR for quantification of magnetic nanoparticles and development of paper-based assay
Authors: Minin A S , Uymin M A , Yermakov A Ye , Byzov I V , Mysik A A , Rayev M B , Khramtsov P V , Zhakov S V , Volegov A V , Zubarev I V 
Published: November 2019

Abstract
H1 NMR relaxometry is a method that is extremely sensitive to the presence of magnetic nanoparticles, which significantly affect the transverse relaxation time of the water proton. Accordingly, the use of magnetic nanoparticles as labels allows detection of even extremely small amounts of the test substance. This paper analyzes the prospects for applying the method of solid-phase NMR-relaxometric determination of biologically active molecules. The nitrocellulose membranes are chosen as a solid phase and nanoparticles based on iron core with a carbon shell are used as magnetic labels. The possibility of detecting small concentrations of magnetic particles in porous medium is demonstrated. Finally, the ability to detect extremely low concentrations of an analyte, in this case, streptavidin protein (0.5 ng/ml to 100 ng/ml), which is actively used in various fields of biology and medicine, is demonstrated.
Two types of magnetite-containing liposomes for magnetocontrolled drug release
Authors: Zharkov M N , Gerasimov M V , Trushina D B , Khmelenin D N , Gromova E V , Yakobson D E , Pyataev M A 
Published: November 2019

AbstractThe paper is dedicated to a comparative study of pharmaceutical properties of magnetite containing liposomes. We have investigated two types of liposomes: 1) magnetic shell liposomes containing magnetic nanoparticles in the coating lipid bilayer and 2) magnetic core liposomes containing the nanoparticles in the internal volume (water phase). Both types of liposomes were obtained by the thin film hydration method from phosphatidylcholine and cholesterol. Fluorescent dye 5,6-carboxyfluorescein was used as a marker substance to indicate release. The dimensional characteristics, the degree of dye release under the influence of an alternating magnetic field, the speed of spontaneous release and the stability of liposomes during storage were investigated. It has been shown that liposomes with nanoparticles in the internal space are more stable, have low rate of spontaneous release of the incorporated substance, but the rate of release under the influence of an alternating field is also low. Liposomes with magnetic nanoparticles inside the lipid bilayer have high release degree influenced by alternating magnetic field, but they are less stable during storage and more prone to spontaneous loss of the active substance.
Influense of various forms of iron on growth of Chlorella vulgaris Beijer culture
Authors: Polynov V A , Maksimova E N , Safronov A P , Kurlyandskaya G V 
Published: November 2019

Abstract
A comparative study of the toxic effect of magnetic nanoparticles of iron oxide (MNPs) and ions of bivalent and trivalent iron in the composition of sulfates on the growth of an intensive culture of Chlorella vulgaris Beijer is provided. The high sensitivity of the introduced biotest is shown for the case of a standard toxicant (potassium dichromate). Using the probit-analysis, and semi-extincting specific growth rate of EC50 culture concentrations were established in four-day experiments, which amounted to 1.3 ± 0.2 mg/l for potassium dichromate, 0.8 ± 0.1 mg/l for ferrous iron, 2.0 ± 0.2 mg/l for trivalent 1 and for MNPs iron oxide – 13 ± 1 mg / l. The probit analysis features and the significantly lower semi-suppressing specific growth rate of the culture in experiments with MNPs compared with ionic iron suggests a possible manifestation of other forms of exposure that are not related to the mechanism of chemical intoxication.
Influence of metal containing nanocomposites on the kinetics of microbial population development
Authors: Simonova E V , Kokorina L A , Denisova T P , Maximova E N , Safronov A P , Sorokina A I , Kurlyandskaya G V 
Published: November 2019

Abstract
Magnetic nanoparticles are promising nanomaterials for biomedical applications. Studies have been conducted to study the effect of iron-containing nanoparticles at concentrations of 1.0 and 10.0 maximum tolerated dose for total iron on the growth and development of the microbial population of E.coli. On the basis of the obtained results, it was found that nanoparticles affect the growth characteristics of E.coli, related to human gram-negative prokaryotic microflora. The level of biological activity of nanoparticles depends on their concentration.
Donor DBH excitons and magnetism of Mn doped ZnO
Authors: Sokolov V I , Gruzdev N B , Vazhenin V A , Fokin A V , Korolev A V , Menshenin V V , Surikov V T , Yemelchenko G A 
Published: November 2019

Abstract
In this paper the results of the study of optical absorption, photo-EPR signals and magnetic measurements of hydrothermal single crystals of zinc oxide doped with manganese were presented. Several lines were detected in optical absorption spectra at the temperature of 4.2 K and 77.3 K for σ- and π- polarizations of light in a 1.72–2.3 eV spectral range. These lines are attributed to a donor exciton [(d5 + h)e] that emerges as a result of the Coulomb binding of a free s electron and a hole, which is localized on p–d hybridized states. Properties of these lines are significantly different from the properties of lines of donor and acceptor excitons in II-VI:3d compounds. In EPR-spectra of Zn1-x
Mn
x
O crystals the intensity of allowed and forbidden EPR-signals of Mn2+ (d
5)-ions does not change under the illumination while the intensity of EPR-signals of unintentional Fe3+ (d
5)-ions decreases by 70 %. The value of the magnetic susceptibility of Zn1-x
Mn
x
O (x = 0.0009) is in linear dependence with temperature, which agrees with the Curie equation. Temperature dependence of the inverse value of the Mn2+ magnetic susceptibility indicates that the exchange interaction in ZnO:Mn crystals is absent. New experimental results allow us to assume that investigated Zn1-x
Mn
x
O (x = 0.0009) samples are semiconductors in the forbidden gap of which the donor level of d5/d4 does not exist. The hybridization of d5 states of Mn2+ and p states of the nearest four oxygen ions O2- leads to pushing out the antibonding DBH-states (d
5 + p) into the forbidden gap. The transitions of electrons from DBH-states to the conduction band provide a broad band of the impurity absorption in ZnO:Mn. Below this band we observed a, b, c and d lines, which are called dbh-donor excitons [(d5+h)e].
Spin current and magnetic measurements in heterostructure SrIrO3/La0.7Sr0.3MnO3
Authors: Shaikhulov T A , Demidov V V , Stankevich K L , Ovsyannikov G A 
Published: November 2019

Abstract
The dc voltage on the film SrIrO3 (SIO) generated under ferromagnetic resonance condition has been studied in the heterostructure based on manganite thin epitaxial films La0.7Sr0.3MnO3 (LSMO). The SIO film is a paramagnetic metal with strong spin-orbit interaction in the temperature range 20-300K. The effect is shown to be caused by two different phenomena: (1) the resonance dc electromotive force related to anisotropic magnetoresistance (AMR) in the manganite film and (2) pure spin current (spin pumping) registered by means of the inverse spin Hall effect in upper layer. We also give the results of the magnetic parameters measuring for the heterostructure SIO/LSMO using ferromagnetic resonance in a wide temperature range.
Generalized Quantum Monte Carlo Algorithm in Eigen Basis
Authors: Kashurnikov Vladimir , Krasavin Andrey , Zhumagulov Yaroslav , Kartsev Petr 
Published: November 2019

Abstract
New generalized continuous-time quantum Monte Carlo algorithm is developed. The algorithm is absolutely universal in the sense that it allows to calculate models specified in an arbitrary basis (in the basis of occupation numbers; in the momentum representation; in the basis of the eigenfunctions of small clusters into which the entire system is divided, or in any other basis): the algorithm requires only the specification of the matrix elements between the basis functions defined in a convenient basis. The implemented algorithm is applied to one-dimensional Hubbard model.
Metal–insulator transition in the antiferromagnetic state of the Hubbard model: analytical theory
Authors: Igoshev P A , Irkhin V Yu 
Published: November 2019

Abstract
In the framework of numerical calculations and analytical expansion in the transfer integral between the next-nearest neighbors t’ and the direct antiferromagnetic (AFM) gap ∆, the metal–insulator transition criterion is obtained, the Hartree-Fock and slave boson approaches being used. In the case of a square lattice, there is an interval of t’ values, for which the metal-insulator transition is a first-order transition, which is due to the Van Hove singularity near the center of the band. For simple and body-centered cubic lattices, the transition from the insulator AFM state occurs to the phase of an AFM metal and is a second-order phase transition; it is followed by a transition to a paramagnetic metal. These results are modified when taking into account the intersite Heisenberg interaction which can induce first-order transitions.
Spin fluctuations of the uranium 5f-electrons in UN according to 14N-NMR data
Authors: Ogloblichev Vasily V , Verkhovskii Stanislav V , Potapov Aleksey M , Germov Aleksandr Yu , Sadykov Almaz F 
Published: November 2019

Abstract
The results of the study of the paramagnetic region of uranium mononitride by the method of nuclear magnetic resonance (NMR)of 14N nuclei are presented.The 14N NMR spectra, the Knight shifts K, the spin-lattice relaxation times T
1 have been obtained within the temperature range T = 60 – 375 K and at magnetic fields 92.8 kOe and 117.5 kOe. The temperature dependence of the Knight shift of the 14N line is proportional to the spin susceptibility χ of 5f-electrons of uranium. The ratio of the experimentally determined value T
T
1
K
2 to the theoretically calculated value of the Korringa contribution is 21.5 (at T = 295 K), which is significantly more than for common metals. This suggests that nuclear relaxation is based on the same mechanism as the Knight shift, namely, the indirect connection between the 14N nuclei and the localized magnetic moments of uranium through conduction electrons. The experimental results on the T-dependence of the spin-lattice relaxation rate of 14N also do not contradict the assumption that uranium mononitride is a concentrated Kondo system.
Temperature hysteresis in bilayer FeRh/PZT structure
Authors: Starkov Ivan , Amirov Abdulkarim , Nikulin Viacheslav , Starkov Konstantin , Starkov Alexander 
Published: November 2019

Abstract
We investigate temperature hysteresis of magnetization in a two-layer composite structure composed of magnetocaloric and electrocaloric materials. The proposed model describes the simultaneous application of electric and magnetic fields. Such an approach allows analysing features of multicaloric effect in bilayer FeRh/PZT structure. To verify the correctness of the developed model, the theoretical results are compared with the experimental data for the multicaloric effect in the FeRh-PZT structure.
Influence of the heat treatment on the chemical composition of the ferromagnetic Ni-Mn-In thin film
Authors: Mashirov A V , Atanova A V , Koshelev A V , Druzhinin A V , Kamantsev A P , Lyange M V , Khovaylo V V , Dilmieva E T , Koledov V V , Shavrov V G 
Published: November 2019

Abstract
The paper presents results of study of the dependence of the Ni-Mn-In film’s composition on the annealing parameters, data of scanning electron microscopy and energy dispersive analysis (EDX spectroscopy). The Influence of annealing of a film in vacuum on the chemical composition is shown. The content of manganese and indium decreases sharply with a rise in temperature up to 900 °C, and in a heating time up to 2 hours. The ferromagnetic Curie point in the investigated Ni-Mn-In films is observed. A decrease of the width of the ferromagnet-paramagnet transition results in the improvement of the crystallinity of the sample after annealing.
The effect of exchange-correlation potentials on magnetic properties of Fe-(Ga, Ge, Al) alloys
Authors: Zagrebin M A , Matyunina M V , Sokolovskiy V V , Buchelnikov V D 
Published: November 2019

Abstract
This work presents a theoretical study of magnetic properties from first-principles calculations for binary Fe100–x

Zx
type alloys (Z = Ga, Ge, Al) in concentration range of 3.125 < x < 21.875 at.%. The both, general gradient approximation and local density approximation are considered for the exchange-correlation functional. Ab initio calculations are performed for A2 and D03 crystal structures. It is shown that for local density approximation, magnetic moments are found in the better agreement with experimental ones. Using the calculated exchange coupling constants for studied compositions, Curie temperatures were estimated by means of mean field approximation. It was found that the obtained Curie temperatures are in qualitative agreement with the experiment.
Determination of saturation magnetostriction of amorphous Fe-Co-P-B ribbons: comparison of various methods
Authors: Sekirin I V , Ignakhin V S , Severikov V S , Grishin A M 
Published: November 2019

Abstract
We present and compare results of measurement of saturation magnetostriction constants of amorphous ribbons Fe80-x
Co
x
P14B6 (x = 23, 25, 28, 32, 40 at.%) and the reference Fe40Ni40P14B6 specimen employing Narita and Becker-Kersten methods. We also modified a strain gauge-based method to enable measurements of complete magnetic field dependence of magnetostriction coefficients.
Charge carrier concentration and structural transition temperatures in Heusler alloys Ni50Mn36Sb14-xZx (Z = Al, Ge; x = 0; 1; 2; 3; 4)
Authors: Emelyanova S M , Dyachkova T V , Tyutyunnik A P , Chistyakov V V , Domozhirova A N , Sauerzopf F , Wang R L , Yang C , Marchenkov V V 
Published: November 2019

Abstract
The temperature dependences of magnetization and electrical resistance of the Ni50Mn36Sb14-xZx (Z = Al, Ge; x = 0; 1; 2; 3; 4) alloys have been used to determine the structural transition temperatures (STT) such as: Ms, Mf, As and Af (temperatures of the start and finish of martensitic and austenitic transformations, respectively). Effect of various parameters (e/a, Vcell, n) on the STT was studied. Using Hall Effect the concentration of charge carriers n* was obtained and it was found that n* is not strongly correlated with a behaviour of STT, there is only a general trend with exceptions.
Magnetic properties of the non-stoichiometric TbCo2Mnx and TbCo2Nix alloys
Authors: Inishev A A , Gerasimov E G , Mushnikov N V , Terentev P B , Gaviko V S 
Published: November 2019

Abstract
The crystal structure, magnetic and magnetothermal properties of non-stoichiometric TbCo2Mn
x
and TbCo2Ni
x
alloys were studied. It was shown that single-phase compounds with the MgCu2-type structure exist up to a certain content of x (x < 0.4 for compounds with Mn and x ≤ 0.1 for compounds with Ni). The concentration changes of the lattice parameter, Curie temperature, magnetic moment of the 3d sublattice in TbCo2Mn
x
and TbCo2Ni
x
alloys were compared. The magnetocaloric effect in alloys were estimated using data of magnetic and heat capacity measurements.
Martensitic transformation and magnetotransport properties of Ni47Mn42In11 alloy
Authors: Kaletina Yu V , Gerasimov E G , Terentev P B , Kaletin A Yu 
Published: November 2019

Abstract
The structure, electrical and magnetic properties of the Ni47Mn42In11 alloy, in which the temperature of the martensitic transformation is close to room temperature and practically coincides with the Curie temperature of austenite, have been investigated. The martensitic transformation in the Ni47Mn42In11 alloy proceeds with the formation of modulated martensite type 14M. It has been established that the spontaneous transformation from martensite to austenite is accompanied by a decrease in the specific resistance of 45%. In the martensitic transformation induced by a magnetic field of 18 kOe, a negative magnetoresistance is observed, reaching ~ 15%.
MFM study of domain structure of CoNi microparticles caused by mechanical stress
Authors: Nurgazizov N I , Biziyaev D A , Bukharaev A A , Chuklanov A P 
Published: November 2019

Abstract
The domain structure of planar CoNi microparticles with the square shape has been studied under mechanical stress. An array of CoNi particles was formed on the surface of thin polished glass by electron beam evaporation. After studying the initial magnetization distribution, the particles were strained along one side due to bending of the substrate. It is shown that the change in the domain structure of CoNi particles depends on the degree of its tension.
Features of focusing magnetoelastic waves in YIG crystals
Authors: Bakharev S M , Borich M A , Savchenko S P 
Published: November 2019

Abstract
The focusing features and caustic of magnetoelastic waves in Y3Fe5O12 (YIG) crystals in the long wavelength approximation are investigated. It is shown that the interaction of phonon and magnetic subsystems leads to pronounced anisotropic properties of magnetoelastic waves. Four magnetoelastic eigenmodes are realized in the crystal, and two of them possess a focusing and caustic in the vicinity of magnetoelastic resonance point. The region of frequencies and wavenumbers of magnetoelastic waves is obtained, where the caustic can be observed. The directions of the focusing and caustic are defined.