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AM: Magnetismus

AM 5: Symposium: Sensorik

AM 5.2: Hauptvortrag

Montag, 27. März 2000, 14:30–15:00, H10

Thin Wires: Magnetization Process and Sensor Applications — •M. Vázquez — Instituto de Magnetismo Aplicado and Instituto de Ciencia de Materiales, P.O. Box 155, 28220 Las Rozas (Madrid), Spain

The study of the magnetic behaviour of thin wires is currently a topic of growing interest due to their outstanding magnetic properties. This behaviour firstly permits to consider them as nearly ideal specimens for basic research in micromagnetics and additionally make them suitable for applications as sensing elements in various technological devices. The following families of wires are considered: i) Amorphous and nanocrystalline wires and glass-coated microwires prepared by rapid solidification into-rotating-water or by quenching and drawing, respectively, and ii) Electrodeposited microtubes onto Cu wires and nanowires filling porous membranes. Diameter of wires is in the range from 100 nm up to 100 micron.
The magnetization process is discussed paying particular attention to bistable wires where a single quite large Barkhausen jump is observed between two stable remanence states. Studies about the propagating wall during reversal and the magnetostatic interactions among wires will be presented. High frequency technically-oriented properties as giant magnetoimpedance and ferromagnetic resonance are also discussed.
Finally, various sensor devices making use of the excellent properties of the wires are introduced. Among others, encoded magnetic tags using magnetic bistability as sensing principle, current and position sensors based on the magnetoimpedance effect, and security fence and signature authentication system based on the magnetoelastic properties.