Magnetic and microwave-absorption properties of SnO-coated α-Fe(Sn) nanocapsules

Abstract

A series of SnO-coated α-Fe solid-solution nanocapsules were fabricated by a modified arc-discharge technique from Fe1−x Sn x targets with x = 0, 2, 3, 4 and 5 at%. The core and shells change with changing Sn concentration (0, 2, 3, 4 and 5 at%) in the Fe1−x Sn x targets used in the preparation. An in-depth study of the complex permittivity and permeability reveals that the SnO-coated α-Fe solid-solution nanocapsules with 3 at% Sn exhibit excellent microwave-absorption properties among the present SnO-coated Fe solid-solution nanocapsules, due to a proper electromagnetic match in the microstructure, the strong natural resonance as well as dipolar polarization mechanisms.

Synthesis, Characterization and Electromagnetic Properties of SnO-coated FeNi Alloy Nanocapsules

“…Similar phenomenon has been analyzed in detail in the previous work [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] . The contributors to magnetic loss, such as magnetic hysteresis, domain-wall displacement, and eddy current loss, can be excluded in the present FeNi/SnO nanocapsules.…”

“…Arc-discharge is a powerful method for preparing nanocapsules and capsulate-nanoparticles of metals with high melting points [9][10][11][12][13][14][15] . In this work, the SnO-coated FeNi nanocapsuels were fabricated by the arc-discharge method.…”

“…The microwave absorbing material is a kind of absorber that can effectively attenuate the intensity of EM waves through dielectric and magnetic losses, or can transform the EM wave energy into thermal energy [6][7][8] . Among the candidates for EM-wave-absorbers, magnetic nanocapsules have attracted particular interest on account of the following facts: (1) the large saturation magnetization and high Snoek limit, (2) the suppression of the eddy current phenomenon, enhancing an effective incidence to EM-wave, and (3) being composites with different kinds of EM-absorber materials 9,10 . Recent studies on carboncontaining magnetic nanomaterials have become more intensive, which can be used as EM interference shielding and absorption materials, due to their lower density and larger resistivity compared with those of metallic magnets [6][7][8][9][10] .…”

“…Among the candidates for EM-wave-absorbers, magnetic nanocapsules have attracted particular interest on account of the following facts: (1) the large saturation magnetization and high Snoek limit, (2) the suppression of the eddy current phenomenon, enhancing an effective incidence to EM-wave, and (3) being composites with different kinds of EM-absorber materials 9,10 . Recent studies on carboncontaining magnetic nanomaterials have become more intensive, which can be used as EM interference shielding and absorption materials, due to their lower density and larger resistivity compared with those of metallic magnets [6][7][8][9][10] . Core-shell structured nanocapsules are a special kind of nanocomposites, which are usually composed of cores and shells of nanometer size that are made of different materials 9 .…”

“…Magnetization measurements were carried out by a vibration sample magnetometer (VSM). The SnO-coated FeNi nanocapsules/paraffin composite was prepared by uniformly mixing FeNi/SnO nanocapsules with paraffin, as described in detail elsewhere [9][10][11][12][13][14][15] , by homogeneously mixing the nanocapsules with paraffin and pressing them into cylinder-shaped compacts. Then the compact was cut into toroidal shape with 7.00 mm outer diameter and 3.04 mm inner diameter The EM parameters for a FeNi/ SnO-paraffin composite containing 40 wt.% FeNi/SnO nanocapsules are determined with the transmission and reflection coaxial line method.…”