Thermal magnetization noise, damping fundamentals, and mode analysis: application to a thin film GMR sensor

Author

Bertram, H.N. ; Safonov, V.L. ; Jin, Z.

Author_Institution

Center for Magnetic Recording Res., California Univ., San Diego, La Jolla, CA, USA

Volume

38

Issue

5

fYear

2002

fDate

9/1/2002 12:00:00 AM

Firstpage

2514

Lastpage

2519

Abstract

Magnetization dynamic equations with thermal fluctuations are derived fundamentally for small amplitude oscillations. A tensor form of phenomenological damping occurs whose components reflect a general elliptical magnetization motion. This analysis implies that thermal energy and associated damping must be applied to independent normal modes of the system. As an example, this formalism is applied to a thin film magnetoresistance sensor to rind the eigenmodes for general nonuniform magnetization variations. Examples are given of both the various modes and the noise power spectra.

Keywords

damping; eigenvalues and eigenfunctions; giant magnetoresistance; magnetic noise; magnetic sensors; magnetic thin film devices; magnetic thin films; magnetisation; magnetoresistive devices; modal analysis; spin dynamics; thermal noise; damping fundamentals; eigenmodes; elliptical magnetization motion; general nonuniform magnetization variations; independent normal modes; magnetization dynamic equations; mode analysis; noise power spectra; phenomenological damping tensor form; small amplitude oscillations; thermal energy; thermal fluctuations; thermal magnetization noise; thin film GMR sensor; Damping; Equations; Giant magnetoresistance; Independent component analysis; Magnetic analysis; Magnetic sensors; Magnetization; Sensor phenomena and characterization; Thermal sensors; Thin film sensors;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2002.801909

Filename

1042243