Morphology dependence of static magnetic and microwave electromagnetic characteristics of polymorphic Fe₃O₄nanomaterials

Abstract

Abstract

Flowerlike iron oxide nanostructures and their application in microwave absorption

“…8b). It is slightly higher than the result of Fe 3 O 4 urchins, which have the optimal reflection loss of À43.2 dB at high frequency of 16.8 GHz [18]. Compared to Fe 3 O 4 nanospheres and sponges, the author pointed out that the excellent microwave absorption performance was ascribed to their unique morphologies.…”

Effect of aspect ratio on dielectric, magnetic, percolative and microwave absorption properties of magnetite nanoparticles

“…12b shows l 0 Ál 00À2 Áf À1 versus frequency. In the resonance conditions the following equation l 0 Ál 00À2 Áf À1 = (2pÁl 0 Ád 2 Ár)/3 is satisfied, if the magnetic loss is only from the eddy currents, the values of l 0 Ál 00À2 Áf À1 would be constant [33]. The values of l 0 Ál 00À2 Áf À1 is almost constant in the frequency range of 14-18 GHz.…”

“…However, Fig. 11d shows that the nanorods have a better EM wave energy loss capability due to the larger attenuation coefficient (a) which can be calculated through the following equation [33]: …”

“…Recently, different hybrid structures of magnetite, such as SiC-Fe 3 O 4 hybrid nanowires [26], phthalocyanine copper/magnetite (CuPc/Fe 3 O 4 ) nanohybrids [27], ultrathin Fe 3 O 4 /carbon nanotube sandwich buckypapers [28], Fe 3 O 4 /graphene nanosheet (Fe 3 O 4 /GNS) composites [29], Fe 3 O 4 @C core-shell nanotubes [30] and MWCNT/Fe 3 O 4 @ZnO heterotrimers [31], have been widely studied for use in EM absorption applications. However, to the best of our knowledge, systematic researches on the effects of different morphological characteristics on the EM properties of magnetite nanoparticles are not abundant [23,32,33]. The aim of this paper is to find out the effect of aspect ratio on the electromagnetic properties for the hydrothermally synthesized and subsequently reduced magnetite nanoparticles.…”

Solvothermal synthesis and electromagnetic absorption properties of pyramidal Ni superstructures

“…EMI pollution can induce significant disturbances in relative systems. 1,2 Enormous studies have been attracted to seek suitable electromagnetic wave absorption materials, such as ferrites, 3,4 polymorphous ZnO, 5,6 soft magnetic metal, [7][8][9] and carbon nanotubes. [10][11][12] Among the candidates for microwave absorbing materials, metallic soft magnetic materials possess many unique features of large saturation magnetization values, Snoek's limit, Curie temperature, and high relative complex magnetic permeability at high frequency ranges.…”