Biased magnetic materials in RAM applications
2007 (English)In: Progress in Electromagnetics Research, ISSN 1559-8985, Vol. 75, 85-117 p.Article in journal (Refereed) Published
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.
Place, publisher, year, edition, pages
2007. Vol. 75, 85-117 p.
Bandwidth, Differential equations, Electric conductivity, Random access storage, Saturation magnetization, Switching, External biasing field, Landau-Lifshitz-Gilbert (LLG) equation, Lorentz-like material
Other Electrical Engineering, Electronic Engineering, Information Engineering
IdentifiersURN: urn:nbn:se:kth:diva-8538DOI: 10.2528/PIER07052501ISI: 000248081200006ScopusID: 2-s2.0-34547246315OAI: oai:DiVA.org:kth-8538DiVA: diva2:13889
QC 201009062008-05-282008-05-282010-09-06Bibliographically approved