The Neel temperature and sublattice magnetization for the stacked triangular-lattice antiferromagnet with a weak interlayer coupling

The quantum Heisenberg antiferromagnet on the stacked triangular lattice with the intralayer nearest-neighbor exchange interaction J and interlayer exchange J' is considered within the non-linear $\sigma$-model with the use of the renormalization group (RG) approach. For J' << J the asymptotic formula for the Neel temperature $T_{Neel}$ and sublattice magnetization are obtained. RG turns out to be insufficient to describe experimental data since it does not take into account the $\mathcal{Z}_2$-vortices. Therefore $T_{Neel}$ is estimated using the Monte-Carlo result for the 2D correlation length [10] which has a Kosterlitz-type behavior near the temperature $T_{KT}$ where the vortices are activated.Comment: 4 pages, 1 figur

Strong fluctuations near the frustration point in cubic lattice ferromagnets with localized moments

Thermodynamic properties of cubic Heisenberg ferromagnets with competing exchange interactions are considered near the frustration point where the coefficient $D$ in the spin-wave spectrum $E_{\mathbf{k}}\sim D k^{2}$ vanishes. Within the Dyson-Maleev formalism it is found that at low temperatures thermal fluctuations stabilize ferromagnetism by increasing the value of $D$. For not too strong frustration this leads to an unusual "concave" shape of the temperature dependence of magnetization, which is in agreement with experimental data on the europium chalcogenides. The phase diagram is constructed by means of Monte Carlo simulation, and suppression of magnetization and Curie temperature is found in comparison with the results of the spin-wave theory. This effect is explained by the the presence of non-analytical corrections to the spin-wave spectrum which are represented in the lowest order by the term $\sim (T/S)^{2} k^{2}\log{k}$.Comment: 5 pages, 5 figures; updated versio

Realization of anisotropic compass model on the diamond lattice of Cu2+^{2+} in CuAl2_2O4_4

Spin-orbit (SO) Mott insulators are regarded as a new paradigm of magnetic materials, whose properties are largely influenced by SO coupling and featured by highly anisotropic bond-dependent exchange interactions between the spin-orbital entangled Kramers doublets, as typically manifested in $5d$ iridates. Here, we propose that a very similar situation can be realized in cuprates when the Cu$^{2+}$ ions reside in a tetrahedral environment, like in spinel compounds. Using first-principles electronic structure calculations, we construct a realistic model for the diamond lattice of the Cu$^{2+}$ ions in CuAl$_2$O$_4$ and show that the magnetic properties of this compound are largely controlled by anisotropic compass-type exchange interactions that dramatically modify the magnetic ground state by lifting the spiral spin-liquid degeneracy and stabilizing a commensurate single-$\boldsymbol{q}$ spiral

отсутствует

The article deals with experimental work to identify fundamental mathematical and statistical characteristics of the developed assessment / diagnostic tool. As a diagnostic tool performs a set of indicators assess communicative skills, eliciting a student's ability and willingness to productive oral and written communication in professional (educational) activitiesВ статье рассматривается экспериментальная работа по определению основных математико-статистических характеристик разрабатываемого оценочного диагностического инструмента. В качестве диагностического инструментария выступает совокупность показателей оценки коммуникативных компетенций, выявляющих способность и готовность студента к продуктивной устной и письменной коммуникации в профессиональной (педагогической) деятельност

CRITERIA FOR ASSESSING ORAL PUBLIC PERFORMANCES OF STUDENTS

In this paper we consider a system of evaluation of oral communication students of secondary vocational education. Given the specificity of speech defined criteria for assessing public speaking: work with the information content of an utterance, compositional alignment of, possession of text, language standards compliance, technology and speech sounds, nonverbal meansВ статье рассматривается система оценивания устной коммуникации студентов среднего профессионального образования. С учетом специфики устной речи определены критерии оценивания публичного выступления: работа с информацией, содержание высказывания, композиционная выстроенность, владение текстом, соблюдение языков норм, техника речи и звуковое оформление, невербальные средства

Найменування меблів та хатнього начиння у творах Т. Г. Шевченка та в українських говірках на півночі Молдови

Ігнатенко Д. А. Найменування меблів та хатнього начиння у творах Т. Г. Шевченка та в українських говірках на півночі Молдови / Д. А. Ігнатенко // Одеський лінгвістичний вісник : зб. наук. праць / [голов. ред. Н. В. Петлюченко] ; Нац. ун-т «Одес. юрид. акад.». – Вип. 3.- Спец. вип., присвячений 200-річчю від дня народження Т. Г. Шевченка. – Одеса : Гельветика, 2014. – С. 76-83.У статті представлено результати компаративного аналізу лексики на позначення меблів та хатнього начиння у творах Т.Г. Шевченка та в українських говірках на півночі Молдови

Integral pattern of bench stability on all adjacent rock of open-pit mine in solid rocks

The article presents the integrated image of bench stability across the entire adjacent pit area on the basis of a probabilistic method to predict the azimuthangular parameters of cracks that limit the potential prisms of the pit bench collapse that are put in the final position, as well as those planned to be set to the limiting contour in the form of a software component as the part of the specialized geoinformation GIS system "Stability