Abstract
The magnetization of a ferro- or ferri-magnetic material has been modeled with the Landau-Lifshitz-Gilbert (LLG) equation. In this
model demagnetization effects are included. By applying a linearized
small signal model of the LLG equation, it was found that the material
can be described by an effective permeability and with the aid of a
static external biasing field, the material can be switched between a
Lorentz-like material and a material that exhibits a magnetic
conductivity. Furthermore, the reflection coefficient for normally
impinging waves on a PEC covered with a ferro/ferri- magnetic
material, biased in the normal direction, is calculated. When the
material is switched into the resonance mode, two distinct resonance
frequencies in the reflection coefficient were found, one associated
with the precession frequency of the magnetization and the other
associated with the thickness of the layer. The former of these
resonance frequencies can be controlled by the bias field and for a
bias field strength close to the saturation magnetization, where the
material starts to exhibit a magnetic conductivity, low reflection
(around -20 dB) for a quite large bandwidth (more than two decades)
can be achieved.
model demagnetization effects are included. By applying a linearized
small signal model of the LLG equation, it was found that the material
can be described by an effective permeability and with the aid of a
static external biasing field, the material can be switched between a
Lorentz-like material and a material that exhibits a magnetic
conductivity. Furthermore, the reflection coefficient for normally
impinging waves on a PEC covered with a ferro/ferri- magnetic
material, biased in the normal direction, is calculated. When the
material is switched into the resonance mode, two distinct resonance
frequencies in the reflection coefficient were found, one associated
with the precession frequency of the magnetization and the other
associated with the thickness of the layer. The former of these
resonance frequencies can be controlled by the bias field and for a
bias field strength close to the saturation magnetization, where the
material starts to exhibit a magnetic conductivity, low reflection
(around -20 dB) for a quite large bandwidth (more than two decades)
can be achieved.
| Original language | English |
|---|---|
| Pages (from-to) | 85-117 |
| Journal | Progress in Electromagnetics Research PIER |
| Volume | 75 |
| DOIs | |
| Publication status | Published - 2007 |
Subject classification (UKÄ)
- Electrical Engineering, Electronic Engineering, Information Engineering