Line form of Mossbauer spectra as an evidence of electron exchange in system CuO-Fe2O3

Investigations of line form and hyperfine structure parameters of Fe 57 nuclei in copper ferrites were carried out by Mossbauer spectroscopy. It is shown that increasing of synthesis temperature leads to redistribution of copper and iron ions among lattice sites. This results in changing of local magnetic fields at iron nuclei and varying of relative intensities of spectrum components. However, detailed study of Mossbauer spectrum line forms for all samples did not allow to detect the influence of nearest cations environment of iron ions in octohedral sites on local field value, which is the case in other spinel structure ferrites. One of possible reasons is strong electron exchange between Cu and Fe ions in octahedral sublattice

Employment of activity-based costing in the process of company business model generation

This paper presents a method of presentation of information for the purposes of managerial decision making in terms of activity-based accounting method and company business model generation. Availability of concerted control strategy and disclosure of a business model in organization's reporting will enable to meet demands of all types of users of information on activity of a company. We offer employment of appraisal of a company value in terms of use of Activity-Based Costing

Evaluation of data representation

In this article the problem of statistically reliable sample size evaluation is considered. The two step procedure proposed by C. Stain allows to determine the sample size. The C. Stain's procedure was used for creating the program `The evaluation of data representation'. The program is a part of the program shell of `Servis-Base' data-base software, developed by the authors. The program was used for the evaluation of the sufficient quantity of measurings in experiments for the determination of the proteinase B.intermedius productivity

Quantum interference of Mössbauer gamma transitions in magnetic materials

In recent years there was the steady increase of actuality of the studies of quantum interference on gamma spectroscopic transitions induced by coherent perturbations. A special attention is paid to gamma transitions in compound (electron - nuclear) systems. In this work it is shown that quantum interference effects (QIE) occur in gamma quantum spontaneous emission spectrum of an electron - nuclear paramagnetic system when electron spin resonance is induced. The occurrence of QIE is connected to preparation of the quantum system initial state. The role of electron relaxation is defined: increase of relaxation rate (as it approaches the Rabi frequency of rf field) leads to extinguishing of QIE. The case of stationary excitation of Mössbauer sublevels by incoherent sources is considered

Quantum interference in Moessbauer resonance fluorescence

We studied the resonance fluorescence of Moessbauer radiation of Fe 57 nuclei with coherently coupled nuclear sublevels. The obtained results prove that the traditional Moessbauer spectroscopy in scattering geometry is effective enough for experimental investigation of the quantum interference of gamma transitions and for studying the coherencies induced by external radiation fields

Optical spectra, crystal-field parameters, and magnetic susceptibility of the new multiferroic NdFe3(BO3)4

We report high-resolution optical absorption spectra for NdFe3(BO3)4 trigonal single crystal which is known to exhibit a giant magnetoelectric effect below the temperature of magnetic ordering TN = 33 K. The analysis of the temperature-dependent polarized spectra reveals the energies and, in some cases, symmetries and exchange splittings of Nd3+ 84 Kramers doublets. We perform crystal-field calculations starting from the exchange-charge model, obtain a set of six real crystal-field parameters, and calculate wave functions and magnetic g-factors. In particular, the values g(perpendicular) = 2.385, g(parallel) = 1.376 were found for the Nd3+ ground-state doublet. We obtain Bloc=7.88 T and |JFN|= 0.48 K for the values of the local effective magnetic field at liquid helium temperatures at the Nd3+ site and the Nd - Fe exchange integral, respectively, using the experimentally measured Nd3+ ground-state splitting of 8.8 cm-1. To check reliability of our set of crystal field parameters we model the magnetic susceptibility data from literature. A dimer containing two nearest-neighbor iron ions in the spiral chain is considered to partly account for quasi-one-dimensional properties of iron borates, and then the mean-field approximation is used. The results of calculations with the exchange parameters for Fe3+ ions Jnn = -6.25 K (intra-chain interactions) and Jnnn = -1.92 K (inter-chain interactions) obtained from fitting agree well with the experimental data.Comment: 13 pages, 8 figures, 2 table

Simulations of magnetic and magnetoelastic properties of Tb 2Ti 2O 7 in paramagnetic phase

Magnetic and magnetoelastic properties of terbium titanate pyrochlore in paramagnetic phase are simulated. The magnetic field and temperature dependences of magnetization and forced magnetostriction in Tb 2Ti 2O 7 single crystals and polycrystalline samples are calculated in the framework of exchange charge model of crystal field theory and a mean field approximation. The set of electron-deformation coupling constants has been determined. Variations of elastic constants with temperature and applied magnetic field are discussed. Additional strong softening of the crystal lattice at liquid helium temperatures in the magnetic field directed along the rhombic symmetry axis is predicted

Quantum interference of mössbauer gamma-radiative transitions in magnetic materials

A method is developed for calculating the resonance fluorescence spectrum of coherent radiation with a finite linewidth from a system whose energy levels are coupled through a strong field. In this case, the shape of the spectrum is essentially affected by quantum interference. The results obtained give impetus to investigations into quantum interference of Mössbauer gamma-radiative transitions in magnetic materials under conditions of induced coherent magnetization dynamics. © 2002 MAIK "Nauka/Interperiodica"

The effect of radiofrequency modulation of 57Fe hyperfine interaction by rotating magnetic field

The effect of 57Fe hyperfine interaction radiofrequency (rf) modulation by external rotating magnetic field was studied in thin Permalloy foil by means of Mössbauer spectroscopy. The rf effect was investigated as a function of intensity for several rf field frequencies. The experiments show that the external rotating rf field causes considerable changes in the hyperfine pattern. The obtained spectra are in disagreement with those obtained by Perlow [Phys. Rev. 172 (1968) 319]. They also are inconsistent with magnetostriction hypothesis. Proceeding from the Mössbauer spectrum analysis one may conclude that the magnetization of investigated foil changes its direction in a complex manner. However, the undertaken experiments show that the essential number of Mössbauer nuclei experience the rotating magnetic field influence

Calculation of Filtration Characteristics of Porous Media by Their Digitized Images with the Use of Lattice Boltzmann Equations

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. We have investigated the features of using STR and MTR models of lattice Boltzmann equations for calculating the filtration characteristics of porous media with the use of their digital images. The results of calculations performed on the basis of these models were compared with the results of analytical calculations made with the use of stationary Navier–Stokes equations and continuity equations. Calculations of the laminar flow in a pipe with the use of the MTR model had a much higher accuracy as compared to analogous calculations by the SRT model and showed independence of the relaxation parameter. It has been established that for fluid flow in pore channels the MRT model and the Navier–Stokes equations give comparable results, whereas in using the SRT model the numerical solution depends on the relaxation parameter