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

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

Assessment of the Size of Rocks in Benchs and Lumpiness of the Blasted Mountain Mass on Pits with Use of Gis Geomix

On the basis of natural researches in career of SC Kovdorsky MCP and computer processing of their results in GIS GEOMIX was developed the photometric method of assessment of blocks (sizes) of breeds in the slope of ledges of a pit, the existing version of this method intended for assessment of lumpiness of mountain mass is improve

On origin of the olivine inclusions from the Kainsaz CO carbonaceous chondrite

Olivine inclusions and chondrules of Kainsaz were formed in a unique process of dust matter melting. The elemental abundances of four fractions of olivine (01) inclusions from Kainsaz were analyzed by INAA. The inclusions of fraction A (160 less than d less than 260 microns) have Fe-Ni grains, the inclusions of fractions B (100 less than d less than 160 microns), C (160 less than d less than 260 microns), and D (260 less than d less than 360 microns) do not. The average elemental enrichment factors relative to CI chondrite for each fraction and chondrules of Kainsaz is shown. The enrichment factors of siderophile Co, Ni, Ir, Au, and non-refractory Na in all fractions are less than 1. The factors of refractory Ca, Sc, La, Sm, and Yb are comparative with the corresponding values of O1 aggregates of Allende CV (average 4.76). For chondrules of Kainsaz these values are lower. Fraction A is enriched in Co, Ir, Au, and relative Ni and CI chondrites: Ir greater than Au greater than Co. The values of (Me/Ni)inc/(Me/Ni)CI are equal to 3.25 for Ir, 2.1 for Au, and 1.2 for Co. The superabundances in Ir and Au relative to Ni witness to formation of Fe-Ni grains of O1 inclusions by agglomeration of grains enriched in refractory metal with grains enriched in non-refractory metal (Au). The enrichments of fraction A in Ca, Sc, La, Sm, and Yb witness about presence of high-temperature phases in O1 inclusions