Intrinsic high frequency permeability of magnetic nanocomposites: uncertainty principle.

The intrinsic high frequency permeability spectra of ferromagnetic conductive nanocomposites containing different volume fractions of nanoscale iron and cobalt have been simulated. A law is proposed to explain the simulated results by assuming that there are plenty of Landau-Lifshitz-Gilbert (LLG) type natural resonances contributing to the intrinsic permeability spectra. The results clearly show that the spectra strongly depend on the distribution of local effective magnetic field, the interaction between the magnetic particles, the inhomogeneous damping constant of LLG precession, and the initial equilibrium states.

Terahertz permeability of hard ferromagnetic L1-FePt alloy nanowire.

It is commonly thought that ferromagnetic materials can not find applications in terahertz domain because of their very weak dynamic magnetic responses. However, our results in this paper show that the terahertz (THz) permeability of an isolated L1-FePt alloy nanowire with super hard ferromagnetic properties is significant at 0.348 THz, as long as it is at proper remanent states (for instance, Mr/Ms = 1.

Discussing the high frequency intrinsic permeability of nanostructures using first order reversal curves.

First order reversal curves (FORC) and intrinsic high frequency permeability spectra have been simulated and analyzed for '1 × 3' iron nanowire (NW) arrays with different interwire distances (D). Discrete interaction constants are found and gradually disappeared with increasing D value. The number of weak resonance peaks decreases with increasing D value.

The effect of ethylene glycol on pore arrangement of anodic aluminium oxide prepared by hard anodization.

The influence of the addition of ethylene glycol (EG) on the pore self-ordering process in anodic aluminium oxide (AAO) membranes prepared by hard anodization (HA) was investigated. It was illustrated that EG has a substantial effect on the pore arrangement of AAO, and it was found that a smaller pore size can be obtained with an EG concentration reaching 20 wt% in aqueous electrolyte. The number of estimated defects of AAO increases significantly with an increase in EG concentration to 50 wt%.

Finite element micromagnetism simulations on the magnetization reversal behaviors of cobalt nanotubes.

In this paper, we have used the finite element micromagnetism theory to simulate the magnetization (M) reversal behaviors of cobalt nanotubes with different lengths (L = 400, 600, 800 and 1000 nm). The inner radius and outer radius of nanotubes are 50 nm and 100 nm respectively. The simulation results show that all the nanotubes exhibit significantly anisotropic behaviors: the easy magnetization axis is along the longitudinal direction.