Исследование магнитных свойств ферроборатов неодима и самария методом спектроскопического эрбиевого зонда

Iron borates NdFe3(BO3)4 and SmFe3(BO3)4 activated with 1% erbium, with a huntite structure (space symmetry group R32) were investigated by the method of erbium spectroscopic probe. From an analysis of the temperature dependence of the transmission spectra in the region of the 4I15/2→4I13/2 transition in the Er3+ ion, it was found that both studied compounds order antiferromagnetically at TN ≈ 33 K into an easy-plane magnetic structure. No other phase transitions were found.

MATHEMATICAL MODELING OF THE CRYSTAL STRUCTURE OF PEROVSKITE-LIKE MATERIALS

The paper presents the calculation of the metric parameters of crystalline compounds according to a given chemical formula and a space symmetry group. The structures of perovskite and double perovskite are considered.

Calculation of One-Electron Wave Functions and Energy Levels of N-Butane Molecule on the Basis of Slater Atomic Orbitals

It is known that the application of the group theory greatly simplifies the problems of polyatomic systems possessing to any space symmetry. The symmetry properties of such systems are their most important characteristics. In such systems, the Hamilton operator is invariant under unitary symmetry transformations and rearrangements of identical particles in the coordinate system. This allows to obtain information about the character of one-electron wave functions — molecular orbitals — the considered system, i.e. to symmetrise the original wave functions without solving the Schrödinger equation.

Understanding the structural, optical, and dielectric characteristics of SrLaLiTe1−xMnxO6 perovskites

In electronic applications, good dielectric permittivity material has huge potential in the capacitive energy storage devices. Herein, in the present work the dielectric study of SrLaLiTe1−xMnxO6 (x = 0.02, 0.04, 0.06, 0.08, and 0.10) double perovskites has been studied and discussed. These compounds were prepared through solid-state reaction method. All of the prepared compounds were confirmed to crystallized in monoclinic structure of P21/n space symmetry with better crystallization when dopant concentrations increased until x = 0.08. The formation of Li–O–Te/Mn bonds in octahedral structures in all compounds were confirmed in this study. The existence of peaks at specific wavenumbers indicated vibrations of B–site cations’ bonds. When dopant amounts were increased from x = 0.02 to x = 0.08, there was an increasing trend of grains sizes formation in the compounds. The discussions on effects of grain sizes towards dielectric properties were included in this paper. Other important results and discussions comprised of the significant effects of dopant on the optical band gap (Eopt) and absorption frequencies of the compounds. The decreasing trend of Eopt towards semiconductor range indicated the compounds’ promising potentials for optoelectronic device application.

Eksplorasi etnomatematika Museum Kereta Kraton Yogyakarta dan pengintegrasiannya ke dalam pembelajaran matematika

Penelitian ini bertujuan untuk mengeksplorasi unsur etnomatematika Museum Kereta Kraton Yogyakarta dan mengintegrasikannya ke dalam pembelajaran matematika. Jenis penelitian ini yaitu penelitian eksploratif. Data yang diperoleh berupa data kualitatif, sumber data penelitian diperoleh melalui observasi, wawancara, dokumentasi, dan studi literatur yang berkaitan dengan Museum Kereta Kraton Yogyakarta. Teknik pengumpulan data dilakukan dengan observasi, wawancara dan dokumentasi. Analisis data dalam penelitian ini menggunakan metode kualitatif-verifikatif, yaitu suatu metode induktif dalam penarikan kesimpulan dimana data dijadikan sebagai dasar untuk menyimpulkan gambaran umum keadaan objek kajian. Hasil penelitian menunjukkan bahwa unsur etnomatematika Museum Kereta Kraton Yogyakarta dapat diintegrasikan ke dalam pembelajaran matematika, diantaranya konsep luas bangun datar, volume bangun ruang, kesimetrisan, dan teselasi/pengubinan. Konsep-konsep tersebut dapat diterapkan dalam pembelajaran matematika sebagai masalah kontesktual sekaligus sebagai salah satu cara mengenalkan unsur budaya kepada siswa sebagai upaya mengembangkan pendidikan karakter siswa.This study aims to identify the potential for integrating ethnomathematics at the Yogyakarta, particularly the Museum of Kereta Kraton (Kraton Railway Museum) into mathematics learning. This type of research was a qualitative descriptive study. The data obtained in the form of qualitative data, the source of research data obtained through observation, interviews, documentation, and study of literature related to Yogyakarta Kraton Railway Museum. The data collection technique was done by observing, interviewing and documenting. The data analysis in this study used a qualitative-verification method, which is an inductive method of drawing conclusions where the data is used as a basis for concluding a general description of the state of the object of study. The results showed that the ethnomatematics of Yogyakarta Kraton Railway Museum has the potential to be integrated into mathematics learning. Ethnomatematics that can be integrated include the concept of flat area, volume of space, symmetry, and tessellation /tiling. These concepts can be applied in mathematics learning as a contextual geometry problem as well as a way of introducing cultural elements to students.

From teaching experience. VIII. Grid ornaments

After 7 symmetry groups of borders, 17 symmetry groups of grid ornaments are the next step on the way to 230 space symmetry groups in the university course of crystallography. A simple derivation of grid ornaments is proposed, combining the search for 10 flat clusters and their translations in 5 parallelogram grids. Analysis of grid ornaments in the urban landscape (artistic mosaics, wall claddings, floorings, etc.) draws students to the actual problem of the prevalence of 230 space symmetry groups in minerals.

Магнитные, электронные и оптические свойства тетраборатов NiB-=SUB=-4-=/SUB=-O-=SUB=-7-=/SUB=- и CoB-=SUB=-4-=/SUB=-O-=SUB=-7-=/SUB=- в трех структурных модификациях

Within a framework of the density functional theory using the VASP software package, physical properties of tetraborate compounds NiB4O7 and CoB4O7 in three structural modifications with space symmetry groups of Pbca, Cmcm and P6522 were calculated. The dependences of the enthalpy of compounds on pressure in studied structural modifications are calculated. The calculated electron densities of states and band structures showed that studied compounds in all considered modifications are dielectrics with a band gap of 3-4 eV. The calculation of the magnetic exchange constants was carried out in the Heisenberg model, which showed qualitative agreement with experiment.