![]() The effects of addition Mg–Ti on microwave absorbing properties calcium hexaferrite were studied in the frequency range of 12–20 GHz. According to this approach, polycrystalline Ca(MgTi) xFe 12−2 xO 19 hexaferrite powders were fabricated by the citrate sol–gel method. But rarely has been investigated microwave absorption magnetic properties calcium hexaferrite. In last two decade, numerous papers have been published on the studies microwave absorption and magnetic properties for M-type barium and strontium ferrites. ![]() In general, hexagonal ferrites are divided into several types: M, X, U, Y, Z and W. Many articles have been reported to develop microwave absorbing materials with hexagonal ferrites. Absorbers come with many several shapes and structures, ranging from thick pyramidal, tile and foam structures. By changing the physical and chemical properties of an absorber, it can exhibit various properties in different frequency bands. The performance of these materials depends on their structure and properties. These materials have absorbed in the megahertz and gigahertz bands. Magnetic absorbers have been based on carbonyl iron and hexaferrites. In a special assortment, absorbent materials are classified into two categories of magnetic and conductive materials. In addition to the characteristic, absorber thickness and weight are also significant attentions. For absorbers, the layout requirements generally are the lowest reflectivity over the widest bandwidth. This absorber has special characteristics such as low resistance and high acceptability. The first radar absorbent material was invented in Netherlands in the 1936. Utilization of radar absorbing materials founded in the 1930s shortly afterwards the advent of radar. The absorption process depends on the dielectric and magnetic properties of the materials. The performance of radar absorbing materials is based on the absorption of radar electromagnetic waves (and conversion to other energies). They have been traditionally used for EMI reduction, antenna pattern shaping and radar cross reduction. It should be pointed out thickness of the composites are 1.9 mm.Īfter World War II, with the progress of radar systems extensive research has been done on radar absorbing materials. Furthermore, the results showed a minimum reflection loss − 31.5 and − 39 dB for composites 0.6 and 0.9, respectively. It is observed bandwidth 6.3 gigahertz (12.5–18.8 GHz with respect to − 15 dB reflection loss) for composite x = 0.6. The observations showed that Ca(MgTi) xFe 12−2 xO 19 nanopowders have extraordinary microwave absorption properties. Microwave absorption properties measured by the standing-wave-ratio method in the Ku band frequency. The hysteresis loops showed saturation magnetization increased from 72 to 98 kA m −1 while coercive force decreased from 1710 to 428 Oe with Mg–Ti content. Results illustrated particles size is less 100 nm. The particle size estimated by the Scherer formula. XRD results verified the formation of M-type hexagonal structures. The microwave absorption, crystal structure, magnetic and morphology of the nanopowders were investigated with vector network analyzer, X-ray diffraction (XRD), vibrating sample magnetometer and transmission electron microscopy. ![]() ![]() The Mg 2+ and Ti 4+ ions substituted M-type Ca(MgTi) xFe 12−2 xO 19 (x = 0, 0.3, 0.6, 0.9) hexagonal ferrites (x = 0, 0.3, 0.6, 0.9) were synthesized by the citrate sol–gel method.
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