Degree Type

Dissertation

Date of Award

1988

Degree Name

Doctor of Philosophy

Department

Electrical and Computer Engineering

First Advisor

Terry A. Smay

Abstract

The magnetization distribution of laminated thin film elements in which two homogeneous magnetic layers are separated by nonmagnetic layer has been studied. These magnetoresistive thin film elements have applications in high density magnetic read heads and nonvolatile computer memory systems. Generally, the elements are 2 x 20 [mu]m with 150 A thick magnetic layers and 50 A thick nonmagnetic layer;The exact analysis of the magnetization distribution of the element can be accomplished by solving the elliptic partial differential equation known as the micromagnetic equation. The boundary condition of the equation is obtained by assuming that the magnetization is pinned to the edge of the element. For the numerical analysis each magnetic layer is divided into 40 x 100 segments. It is assumed that only coherent rotation is allowed inside a segment. The demagnetizing field is obtained by integrating the surface poles generated at the boundaries of the segments. The standard five-point method is used to solve the equation. The point iteration with the updated demagnetizing field plays critical role in getting the convergence. Because of the small dimension of the elements, exchange and demagnetizing fields play significant roles in the equation. The two different shapes of elements considered are rectangular shape and diamond shape. Each shape is solved with its uniaxial anisotropy axis either parallel or perpendicular to the long dimension of the element. The present solutions suggest that the transverse diamond type element shows the smoothest angle distribution.

DOI

https://doi.org/10.31274/rtd-180813-11564

Publisher

Digital Repository @ Iowa State University, http://lib.dr.iastate.edu/

Copyright Owner

Hah Young Yoo

Language

en

Proquest ID

AAI8825967

File Format

application/pdf

File Size

87 pages

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