The Physical Model of Formation of Hexagonal Ferrites BaFe12O19

To identify the features of structural transformations occurring during the formation of the crystal lattice of hexagonal barium ferrite were studied the following issues: a) component defined that are structural element in the reaction of solid-phase synthesis of ferrites BaFe12O19; b) the phase composition set of the reaction products formed in mixtures of BaCО3 – Fe2O3; c) a crystal-chemical model developed allows visually describe the transformation of -Fe2O3 – BaFe12O19

The Physical Model of Formation of Hexagonal Ferrites BaFe12O19

To identify the features of structural transformations occurring during the formation of the crystal lattice of hexagonal barium ferrite were studied the following issues: a) component defined that are structural element in the reaction of solid-phase synthesis of ferrites BaFe12O19; b) the phase composition set of the reaction products formed in mixtures of BaCО3 – Fe2O3; c) a crystal-chemical model developed allows visually describe the transformation of -Fe2O3 – BaFe12O19

On Influence of Magnetic Fields and Excitation Conditions on the Magnetization Distribution in Microwire Magnetoimpedance Element

One of important condition for the successful development of effective magnetic field sensors based on amorphous ferromagnetic microwires is to identify factors affecting the reversal processes in the surface layer of the magnetoimpedance wire. In this paper, the distribution of magnetization is considered as a function of the magnetic properties of the wire material, current flowing through it, strength and orient a-tion of the external magnetic field. The impact of these factors on the performance of the sensor is analyzed on the basis of the numerical simulation of the sensor element. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3640

Obtaining Hexagonal Ferrites for Substrates Microstrip Microwave Devices of mm-Range of LTCC-technology

In the work by the method low temperature co-fired ceramics (LTCC) obtained samples of isotropic and anisotropic polycrystalline hexaferrite BaFe12O19 and SrFe12O19. Using in the LTCC-technology the pressing operation for samples (tablets) in a magnetic field produces anisotropic hexaferrites, pressing without a magnetic field - isotropic hexaferrites. Application in the LTCC-technology molding process tape produces exclusively isotropic samples

Obtaining and Properties of Hexaferrite BaFe12O19 for High-coercivity Permanent Magnets and Substrates Microstrip Microwave Devices of mm-Range

In the work by ceramic technology produced samples isotropic and anisotropic polycrystalline hexaferrite BaFe12O19 and investigated their properties. It is shown that as the permanent magnets can be used both types of samples, whereas for substrates microstrip microwave devices mm-range expedient to use only anisotropic polycrystalline hexaferrite BaFe12O19

Influence of Surfactants on the Activity Powders of Barium Hexaferrite, Prepared by Wet Grinding

Study the influence of citric acid and isopropyl alcohol on processes of wet grinding mixture of starting ferrite constituting components and synthesized ferrite charge. Found that the introduction of additives during wet grinding allows to significantly reduce the temperature of synthesis and sintering ferrite raw blanks. Increased activity of powders is explained by the formation of active the gelled layers on the surface of particles in the process of wet grinding

On Properties of Magneto-dielectric Composites in the Effective Medium Approximation

The development of ultra-broadband composite absorbers of electromagnetic waves depends largely on optimal combination of the medium characteristics that determine their absorption capacity and conditions for impedance matching and destructive interference. It is possible to achieve a higher absorption level in a wider frequency band by combining a variety of mechanisms enhancing the loss of electromagnetic field energy, for example, by combining specific constituents in a composite matrix. The analysis of various mix-ing models for constituent parameters is carried out in the effective medium approximation for ferrite-dielectric composites. It appears that the standard mixing rules do not explain the increase in the effective permittivity of ferrite composites in comparison with that of bulk ferrites. The proposed mechanism of such increase is based on the conductive properties of the ferrite granules and the equivalent capacitance effect. The developed model of permittivity calculation is based on the equivalent capacitor circuits and gives a satisfactory agreement with the experimental data. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3640

Influence of Magnetic Pulseprocessing on Oxide Materials Physics and Mechanical Properties

Internal stresses, specific single-crystal blocks, stoichiometric impurity of oxides composition and other factors lead to low strength properties of ferromagnetic iron oxides. Weakening of such defects and increa s-ing iron oxides microhardness, their fracture and mechanic strength are possible by using magnetic pulse processing. The results of experimental studies of the magnetic pulse field effecting on the iron oxides strength properties are shown. Mössbauer spectroscopy, porosimetry, X-ray structure analysis are used to find the mechanisms of this effect. The strength properties change is the result of set of microscopic and quantum effects superposition. It provides easy defects restructuring of solids: vacancies, dislocations, voids. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3636

Influence of Surfactants on the Activity Powders of Barium Hexaferrite, Prepared by Wet Grinding

Study the influence of citric acid and isopropyl alcohol on processes of wet grinding mixture of starting ferrite constituting components and synthesized ferrite charge. Found that the introduction of additives during wet grinding allows to significantly reduce the temperature of synthesis and sintering ferrite raw blanks. Increased activity of powders is explained by the formation of active the gelled layers on the surface of particles in the process of wet grinding

High Sensitivity Magnetic Sensors Based on Off-diagonal Magnetoimpedance in Amorphous FeCoSiB Wires

The magnetoimpedance (MI) effect has a potential for the development of high performance magnetic sensors. For sensor applications, off-diagonal configuration is preferable when the MI element is excited by ac current and the output is detected from the coil. In the present work, the off-diagonal sensor design was advanced by utilising a complex waveform excitation produced by a microcontroller and applied to a multiple wire MI element. For optimised excitation with a waveform close to a positive half sine form and characteristic frequency of 8 MHz the field resolution of about 60 mV/Oe was achieved. The pulse excitation does not require an additional bias since it includes controllable low frequency components. The concept of microcontroller driven sensor element could be attractive for the development of intellectual sensors. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3358