Fabrication and electromagnetic wave absorption properties of amorphous Ni—P nanotubes

Abstract

Amorphous Ni-P nanotubes are fabricated through electroless chemical deposition inside an anodic aluminum oxide template. The hysteresis loops of Ni-P nanotube arrays are each found to exhibit an unusual isotropic behaviour, which is believed to be due to the competition results between the shape anisotropy and the magnetostatic interaction among nanotubes. The dynamic dependence of permittivity on the frequency spectrum is fitted to the Lorentzian-type dispersion law. The permeability dispersion behaviours have been fitted based on the Kittel equation. Electromagnetic wave absorption properties of Ni-P nanotubes/paraffin composites with different values of thickness (t) are clearly shown by a three-dimensional graph. Furthermore, the bandwidths of composites with different "t" values can be well presented by a two-dimensional contour graph, which is a novel presentation form. The results show that the composites each have a good microwave absorption performance with t larger than 5.5 mm and with the frequency around 8 gigahertz.

Electromagnetic wave absorbing properties and hyperfine interactions of Fe—Cu—Nb—Si—B nanocomposites

“…5(b). Once the dependences of permittivity and permeability on frequency have been measured, the electromagnetic wave (EM) absorption of an absorber containing these ferromagnetic flakes with the reported nanocomposite features can be evaluated by the follow-ing equations, and the properties of EM absorption are characterized by the reflection loss (RL): [19][20][21] Z in = Z 0 µ r /ε r tanh j 2π f t c…”

Fabrication of CoFe 2 O 4 ferrite nanowire arrays in porous silicon template and their local magnetic properties

“…Recently, one-dimensional (1D) magnetic structures, especially magnetic nanowire arrays, have attracted much attention due to their unique potential applications in magnetic integrated nanosystems, perpendicular magnetic records, microwave absorbing and spintronic nanodevices. [1][2][3][4] Cobalt spinel ferrite CoFe 2 O 4 (CFO) is well known for its high coercivity, giant magnetostriction, unique light-induced coercivity change, and remarkable chemical stability. CFO has various applications, such as humidity sensors, photodetectors, biomedical, magnetoelectric devices.…”

Enhancement of microwave absorption of nanocomposite BaFe12O19/α-Fe microfibers

“…Recently, one-dimensional (1D) materials have been widely used as microwave absorbers owing to their large specific areas, high aspect ratios, and strong shape effects. [15][16][17][18][19][20] Shen et al [21] investigated the microwave absorption of the nanocomposite BaFe 12 O 19 /Ni 0.5 Zn 0.5 Fe 2 O 4 microfibers. Their results showed that when the specimen thickness is 3 mm, the minimum reflection loss (RL) reaches −35.5 dB at 12.4 GHz, with a wide absorption bandwidth (RL < −20 dB) from 9.1 to 15.7 GHz.…”