Rambutan-like Ni/MWCNT heterostructures: Easy synthesis, formation mechanism, and controlled static magnetic and microwave electromagnetic characteristics

The hierarchical three-dimensional cobalt superstructure: Controllable synthesis, electromagnetic properties and microwave absorption

“…To study the permeability of the cobalt particles, the equation l 00 ðl 0 Þ À2 f À1 ¼ 2 3 pl 0 d 2 r is introduced [28][29][30], where l 0 represents vacuum permeability, d represents thickness of composite and r represents electric conductivity of composite. By analyzing the equation, we know that if the l 00 ðl 0 Þ À2 f À1 keeps a constant with increasing the frequency, the magnetic loss mainly stems from eddy current loss.…”

Structural, Field Emission and Ammonia Gas Sensing Properties of Multiwalled Carbon Nanotube-Graphene Like Hybrid Films Deposited by Microwave Plasma Enhanced Chemical Vapor Deposition Technique

“…MWCNT spread all over the substrate at the deposition temperature of 600 C. Figure 6(c) shows clustering of MWCNT in the flowered like structure at the deposition temperature of 700 C. The clustering of MWCNT in such a manner is an interesting phenomenon. Tong et al 25 have also found such a uniform and typical rambutan (tree bearing spiny red fruit) like nanostructure on octahedral nickel oxide (NiO) in the powder form and proposed that initially carbon atoms absorbed on octahedral NiO particle reduces them into Ni. Carbon atoms diffused through nickel and MWCNT are grown by the tip growth model.…”

“…26 Generally, amorphous carbon changes into graphite at high temperature (from 2500-3500 C) in the absence of a catalyst, whereas in the presence of a catalyst (Ni), it transforms into graphitic at low temperature (from 600-900 C). 25 This is a post MWCNT deposition phenomenon, where first MWCNTs are deposited on nickel substrate with some carbon atoms diffused to nickel foil. After MWCNT is deposited, substrate is cooled very fast by shutting off the power to the heater.…”

Synthesis, permeability resonance and microwave absorption of flake-assembled cobalt superstructure

“…10,22,23], where 0 μ represents the vacuum permeability, d represents the thickness of composite and σ represents the electric conductivity of composite. If f ( ) 2 1 μ μ ‵‵ ‵ − − is independent of frequency in the frequency range of 1-18 GHz, the magnetic loss mainly stems from the current eddy.…”