AN INVESTIGATION OF SOME EXPERIMENTAL METHODS FOR OBSERVING MAGNETIC DOMAIN PATTERNS IN THIN FILMS
Date
1969-09
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ORCID
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Degree Level
Doctoral
Abstract
Aspects of optical and electron optical methods of observ—ing magnetic contrast from thin ferromagnetic films have been investigated.
In particular, the designs of two coherence spoilers constructed in the of spinning disks for use with a CW laser source to provide illumination in the Kerr effect microscope are described. The extreme monochromatism of the laser beam has enabled a significant improvement in magnetic contrast to be realized over that obtained using conventional light sources, whilst eliminating most of the problems associated with coherent imaging.
Lorentz contrast has been demonstrated with thin ferromagnetic films in the AEI — EM6G electron microscope in the transmission mode. A technique is described with which magnetic and nonmagnetic diffraction effects may easily be distinguished in high resolution Lorentz force on the direction of the probing electron's velocity in passing through the magnetic film.
A theoretical and experimental investigation of the feasibility of using reflection electron microscopy for imaging domain structures was undertaken and the conclusion reached that this is not a suitable method with the present apparatus.
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Degree
Doctor of Philosophy (Ph.D.)
Department
Electrical Engineering