Münster 1999 – scientific programme

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AM: Magnetismus

AM 3: Dünne magnetische Schichten und Vielfachschichten, magnetooptische Schichten II

AM 3.1: Invited Talk

Monday, March 22, 1999, 14:30–15:15, F5

Lorentz microscopy studies of magnetisation reversal in continuous and patterned magnetic multilayers — •J. N. Chapman, P. R. Aitchison, J. P. King, and K. J. Kirk — Department of Physics and Astronomy, University of Glasgow, Glasgow G12 8QQ, Scotland, UK.

Transmission electron microscopy has been used extensively to investigate the magnetisation reversal mechanisms in materials of interest for advanced sensing or storage application. The experimental procedure adopted is to subject the specimen to a vertical magnetic field of the experimenter’s choosing and to then tilt the specimen about a horizontal axis so that it is subjected to a varying field in its plane. As the electron optical conditions remain unchanged throughout the experiment, observations can be made in real time. Much of the recent work has concerned spin-valve material where the reversal mechanism is found to depend strongly on the anisotropies present, the coupling between the free and the pinned layers and the orientation of the applied field. Further complications are introduced when the spin-valve material is patterned to micron or sub-micron sized dimensions as is inevitably the case for device application. Magnetostatic effects can now play a dominant role and we discuss how the magnetic behaviour changes. Finally we comment on differences in magnetisation reversal mechanisms in spin-valves and other multilayer magnetic films displaying the giant magnetoresistance effect.