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Svetoslav Kolev  - - - 
Publication Record
Distribution of Articles published per year 
(2002 - 2018)
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BOOK-CHAPTER 0 Reads 0 Citations Nanosized Ferrite Materials for Absorption of and Protection from MW Radiation Svetoslav Kolev, Tatyana Koutzarova Published: 27 May 2018
NATO Science for Peace and Security Series B: Physics and Biophysics, doi: 10.1007/978-94-024-1298-7_26
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BOOK-CHAPTER 7 Reads 0 Citations A Comparative Study of the Morphology of Y-Type Hexaferrite Powders Obtained by Sol-Gel Auto-Combustion and Ultrasonic C... Borislava Georgieva, Svetoslav Kolev, Chavdar Ghelev, Tatyan... Published: 27 May 2018
NATO Science for Peace and Security Series B: Physics and Biophysics, doi: 10.1007/978-94-024-1298-7_3
DOI See at publisher website
PROCEEDINGS-ARTICLE 65 Reads 0 Citations Study of the Properties of Co-Substituted Ba2Mg2Fe12O22 Hexaferrites Tatyana Koutzarova, Borislava Georgieva, Svetoslav Kolev, Ki... Published: 17 May 2018
Proceedings of The 3rd International Electronic Conference on Materials Sciences, doi: 10.3390/ecms2018-05229
DOI See at publisher website ABS Show/hide abstract
Multiferroic materials, in which long-range magnetic and ferroelectric orders coexist, have recently been of great interest in the fields of both basic and applied sciences. The Y-type hexagonal ferrite Ba2Mg2Fe12O22 is an example of a multiferroic material. Its single crystals have a relatively high spiral-magnetic transition temperature (~200 K), show multiferroic properties at zero magnetic field, and the direction of the ferroelectric polarization can be controlled by a weak magnetic field (< 0.02 T) [1]. We present a study of the influence of substituting the Mg2+ cations in the Y-type Ba2Mg2Fe12O22 hexaferrites with a magnetic cation, such as Co2+, on the structural and magnetic properties. The Ba2Mg0.4Co1.6Fe12O22 powder was synthesized by sonochemical co-precipitation. High-power ultrasound was applied to assist the co-precipitation process. The precursors produced were synthesized at 1170°С. The XRD spectra of the powders showed the characteristic peaks corresponding to the Y-type hexaferrite structure as a main phase and some CoFe2O4 impurity (< 2%) as second phase. This was also confirmed by Mössbauer spectroscopy measurements. The magnetization values at 50 kOe were 30 emu/g and 26.6 emu/g at 4.2 and 300 K, respectively. The ZFC and FC magnetization curves were obtained at a magnetic field of 500 Oe. The magnetic measurements revealed a magnetic phase transition at 200 K from ferrimagnetic-to-helical spin order. Such a transition is considered as a precondition for the material to exhibit multiferroic properties. [1] K. Taniguchi, N. Abe, S. Ohtani, H. Umetsu, T. Arima, "Ferroelectric polarization reversal by a magnetic field in multiferroic Y-type hexaferrite Ba2Mg2Fe12O22", Appl. Phys. Express, vol. 1, art. num. 031301, 2008.
PROCEEDINGS-ARTICLE 4 Reads 0 Citations Characterization of Y-type hexaferrite Ba2Mg2Fe12O22 powders Borislava Georgieva, Kiril Krezhov, Svetoslav Kolev, Chavdar... Published: 01 May 2017
2017 40th International Spring Seminar on Electronics Technology (ISSE), doi: 10.1109/isse.2017.8000885
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PROCEEDINGS-ARTICLE 1 Read 1 Citation Influence of the preparation methods on the structure and magnetic properties of nanosized Al-substituted barium hexafer... P. Peneva, T. Koutzarova, Svetoslav Kolev, Ch. Ghelev, B. Ve... Published: 01 January 2016
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Article 0 Reads 1 Citation Influence of the agglomeration in the initial suspension (ferrofluid) on the oriented magnetic structure Svetoslav Kolev, T Koutzarova Published: 15 May 2014
Journal of Physics: Conference Series, doi: 10.1088/1742-6596/514/1/012021
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