Dimerization and low-dimensional magnetism in nanocrystalline TiO2 semiconductors doped by Fe and Co

The report is devoted to an analysis of the structural and magnetic state of the nanocrystalline diluted magnetic semiconductors based on TiO2 doped with Fe and Co atoms. Structural and magnetic characterization of samples was carried out using X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), X-ray absorption spectroscopy (XAS), electron paramagnetic resonance (EPR) spectroscopy, SQUID magnetometry, and the density functional theory (DFT) calculations. Analysis of the experimental data suggests the presence of non-interacting paramagnetic Fe3+ and Co2+ ions in the high-spin state and negative exchange interactions between them. The important conclusions is that the distribution of dopants in the TiO2 matrix, even at low concentrations of 3d-metal dopant (less than one percent), is not random, but the 3d ions localization and dimerization is observed both on the surface and in the nanoparticles core. Thus, in the paper the quantum mechanical model for describing the magnetic properties of TiO2:(Fe, Co) was suggested. The model operates only with two parameters: paramagnetic contribution of non-interacting 3d-ions and dimers having different exchange interactions between 3d magnetic carriers. © Published under licence by IOP Publishing Ltd

Magnetic and magnetocaloric properties of (MnCo)1-xGe compounds

The crystal structure, magnetic properties, and heat capacity of the (MnCo)1-xGe compounds with x ≤ 0.05 have been studied. It was found that, as the deviation from the MnCoGe stoichiometric composition increases, the temperature of structural transition from the low-temperature phase with the orthorhombic TiNiSi-type structure to the high-temperature phase with the hexagonal Ni2In-type phase decreases rapidly, whereas the magnetic ordering temperature varies slightly. The temperature of structural transition for the composition with x = 0.02 approximately coincides with the Curie temperature of the hexagonal phase, and the transition is accompanied by a significant entropy change, namely, ΔS = 34 J/(kg K). The application of high magnetic field in the transition-temperature range causes an increase in the relative volume of the orthorhombic phase. An analysis of magnetocaloric properties of these compounds, which was performed with the formal application of the Maxwell's relationship near the temperature of first-order structural phase transition, is shown to give overestimated values of the entropy change. © Pleiades Publishing, Ltd., 2013

Russian Early Symbolist Prose and Britain Modernists. F. Sologub and K. Mansfield

The problem of foreign culture reception of prosaic texts served in the early symbolic discourse of Russian literature is considered. They are clearly common and the possibility of this discourse`s influence on representatives of English literary tradition of the first decades of the 20th century. The relevance of the research is due to a continued dispute about the significance of Russian literature as a part of world culture. The novelty of the research is due to address the period of becoming modernism as Art system. "New art" reopened many subjects and motives (childhood, freaks, evil attractiveness, aesthetics of death). Its pattern of transition from typing to symbolism reflected the dynamic of the artistic process in the common cultural space in the conditions of intensive globalization. The results of a comparative analysis of the stories of F. Sologub and K. Mansfield are presented. The necessity of addressing to these materials during the teaching in the philological audience is substantiatedРассмотрен вопрос инокультурной рецепции прозаических текстов, входящих в раннесимволистский дискурс русской литературы, и возможность его влияния на представителей английской литературной традиции начала XX в., что говорит о значении русской литературы как части мировой культуры. Показаны становление модернизма как художественной системы, его темы и мотивы (детство, странные люди, притягательность зла, эстетизация смерти), а также принцип ухода от типизации к символичности в условиях интенсивной глобализации. Представлены результаты сопоставительного анализа рассказов Ф. Сологуба и К. Мэнсфилд, обоснована необходимость обращения к данным материалам в процессе преподавания в иностранной филологической аудитори

On the Phenomenon of Urban Culture in F. Sologub’s Prose

The article examines the reflection of some aspects of urban culture in the work of Fyodor Sologub. Much attention is paid to the fact that the modernists considered the phenomenon of the city as a universal, idealistically meaningful model of life. The question about the image of the City, the mythologized space in the work of Russian Symbolists, is raised. A review of prose texts by F. Sologub, whose work belongs to this literary direction, has also been carried out. The article presents the results of the analysis of the writer's works, in which urban themes are an important component of the ideological and semantic content. The presented author's concept makes it possible to trace in the writer's work not only the allusions of the ancient Greek and Gnostic myths but also the reconsidered facts of the author's biography and social life of Russia. The issues of the reception of this discourse in the world of Chinese culture are considered.Рассматривается отражение некоторых аспектов городской культуры в творчестве Ф. Сологуба. Большое внимание уделяется рассмотрению феномена города у модернистов как универсальной, идеалистически осмысленной модели бытия. Поднимается вопрос об образе Города - мифологизированного пространства в творчестве русских символистов. Выполнен также обзор прозаических текстов Ф. Сологуба, чье творчество относится к этому литературному направлению. Представлены результаты анализа произведений писателя, в которых городская тематика является важной составляющей идейно-смыслового содержания. Выделены в творчестве писателя не только аллюзии древнегреческого и гностического мифов, но и переосмысленные факты авторской биографии и общественной жизни России. Затронуты вопросы рецепции этого дискурса в мире китайской культуры

Unconventional magnetism of non-uniform distribution of Co in TiO2 nanoparticles

High-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD) analysis, electron paramagnetic resonance (EPR), X-ray absorption spectroscopy (XAS), magnetic methods, and density-functional theory (DFT) calculations were applied for the investigations of Co-doped anatase TiO2 nanoparticles (∼20 nm). It was found that high-spin Co2+ ions prefer to occupy the interstitial positions in the TiO2 lattice which are the most energetically favourable in compare to the substitutional those. A quantum mechanical model which operates mainly on two types of Co2+ – Co2+ dimers with different negative exchange interactions and the non-interacting paramagnetic Co2+ ions provides a satisfactorily description of magnetic properties for the TiO2:Co system. © 2020 Elsevier B.V.Russian Foundation for Basic Research. Ministry of Science and Higher Education of the Russian Federatio

Magnetic viscosity dependence of δm plots for a NdFeB-based alloy

A DC demagnetized Nd2(Fe0.8Co0.2)14B melt-spun ribbon was studied in this work. Magnetization and demagnetization processes and, as consequence, δM(H) plots were shown to depend on the magnetic viscosity. The magnetic viscosity coefficient, S, was also determined in positive and negative fields. © 2019 Author(s)

Magnetic viscosity dependence of δM plots for a NdFeB - based alloy

The study was supported by Minobrnauki of Russia (themes "Alloys" and "Magnet") and by grants No.18-32-00220 of Russian Foundation for Basic Research

Structure and properties of the intercalation compound FexTiTe2

The FexTiTe2 system, which belongs to the class of materials with the electronic spectrum containing below the Fermi level the band of localized states with a strong temperature dependence of the band width, has been investigated experimentally. Heating of the material leads to a broadening of the band of localized states. When the top of this band crosses with the Fermi level, the effect of retrograde solubility is observed in the system; i. e., the metal precipitates to the composition ensuring the absence of increase in the Fermi energy during heating. The influence of the band of localized states on the structure of the material and its magnetic and electrical properties has been analyzed. © 2013 Pleiades Publishing, Ltd