Biased magnetic materials in RAM applications
Author
Summary, in English
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).
Publishing year
2007
Language
English
Publication/Series
Technical Report LUTEDX/(TEAT-7155)/1-29/(2007)
Full text
Document type
Report
Publisher
[Publisher information missing]
Topic
- Electrical Engineering, Electronic Engineering, Information Engineering
Status
Published
Report number
TEAT-7155
Research group
- Electromagnetic theory