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,
we found that there will be two distinct resonance frequencies in
the reflection coefficient, one associated with the precession
frequency of the magnetization and one 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, one can achieve low reflection (around -20
dB) for a quite large bandwidth (more than two decades).
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,
we found that there will be two distinct resonance frequencies in
the reflection coefficient, one associated with the precession
frequency of the magnetization and one 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, one can achieve low reflection (around -20
dB) for a quite large bandwidth (more than two decades).
| Original language | English |
|---|---|
| Publisher | [Publisher information missing] |
| Number of pages | 29 |
| Volume | TEAT-7155 |
| Publication status | Published - 2007 |
Publication series
| Name | Technical Report LUTEDX/(TEAT-7155)/1-29/(2007) |
|---|---|
| Volume | TEAT-7155 |
Bibliographical note
Published version: Progress In Electromagnetics Research, Vol. 75, pp. 85-117, 2007.Subject classification (UKÄ)
- Electrical Engineering, Electronic Engineering, Information Engineering