Phosphate bonded CoFe2O4-xBaTiO3 multiferroic composite ceramics: shielding efficiency vs temperature in microwaves
2Institute for Physical Chemical Problems, Belarusian State University, Minsk, Belarus
3Department of Characterisation of Materials Structure, Center for Physical Sciences and Technology, Vilnius, Lithuania
4Institute of Photonics, University of Eastern Finland, Joensuu, Finland
Nowadays, in the 5G era with electromagnetic (EM) interference problems that seriously affect the normal operation of electronic components, development of the materials with high EM shielding ability is extremely needed. Both distinguished microwave EM shielding cases, non-reflective planar surface with back reflector (Salisbury screen) and free-standing non-transmitting layer have already found a huge number of potential applications including antennas, radars, anechoic chambers, cloaking, etc. [1]. However, despite the significant progress, there are not many works [2] concentrated on the temperature dependence of shielding efficiency, although slight temperature changes might dramatically affect the electromagnetic response of the composite. The list of promising candidates for EM shielding applications is not limited to carbon materials and their structures [2], particularly, previously it was demonstrated that the phosphate bonded inorganic materials [3] are also prospective options from this point of view. Besides, addition of the hexaferrites or spinels (CoFe2O4, or NiFe2O4) is interesting due to possible synergism between different phases. Ferroelectrics, like BaTiO3 have high dielectric permittivity and therefore are prospective for EM shielding in microwaves.
The present work is devoted to numerical and experimental studying (for the case of BaTiO3-CoFe2O4 - based phosphate bonded unsintered ceramics) of the influence of the temperature and composition on shielding efficiency. A series of CoFe2O4–xBaTiO3 (x=0.4–0.9) will be studied both in ’Salisbury screen’ geometry and as a free-standing film in the frequency range of 25–54 GHz and temperature interval of 120-500 K. It will be shown that the electromagnetic response of multiferroic composite ceramics in microwaves is very sensitive to the small temperature variations (about 5–10 K).
[1] R. Panwar, J.R. Lee, Functional composites and structures, 1(3),032001(2019).
[2] Z. Barani, et al., Advanced Electronic Materials, 6(11),2000520(2020).
[3] A. Plyushch, et al., Applied Physics Letters, 114(18),183105(2019).
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