Dynamic magnetic losses in powders consisting of metallized dielectric particles at microwaves
| Autor: | Dmitriy A. Kalganov, Igor V. Bychkov, Aleksandr A. Fediy, Olga G. Kharitonova, Anton P. Anzulevich, Leonid N. Butko, Dmitriy A. Pavlov, Sergey G. Moiseev, Vasiliy D. Buchelnikov |
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| Rok vydání: | 2017 |
| Předmět: |
010302 applied physics
Electromagnetic field Permittivity Materials science Physics::Optics Metamaterial 02 engineering and technology Dielectric Physics::Classical Physics 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Electronic Optical and Magnetic Materials Magnetic mirror 0103 physical sciences Composite material 0210 nano-technology Relative permeability Electrical conductor Electrical impedance |
| Zdroj: | Journal of Magnetism and Magnetic Materials. 444:307-312 |
| ISSN: | 0304-8853 |
| Popis: | In this study the interaction of microwaves with dielectric spherical particles covered by conductive shell was modelled. Dependencies of effective permittivity and permeability of powders, consisting of core-shell metallized dielectric particles, on frequency, radius and permittivity of core, as well as thickness and conductivity of metallic shell were obtained. The present paper introduces a novel technique for calculation of effective permittivity and permeability based on results of direct finite element method simulations of electromagnetic fields within the model. Equations for calculation of effective electrodynamics parameters were derived from a combination of surface impedance equations and impedance values for an ideal conductor and an ideal magnetic mirror. The contribution of electric and magnetic losses was evaluated and compared for completely conductive particles and dielectric particles with a conductive shell. It was identified that for completely conductive particles and for metallized dielectric particles the imaginary part of effective permeability is orders of magnitude greater than the imaginary part of effective permittivity. In addition, the imaginary part of effective permeability of core-shell metallized dielectric particles can be nearly twice as greater than the one of completely conductive particles. Moreover, the maximum of dynamic magnetic losses is reached when the conductive shell thickness is less than skin depth. Therefore, we can conclude that dynamic magnetic losses is the main mechanism of microwave heating of such particles. |
| Databáze: | OpenAIRE |
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