When two ferromagnetic thin films are separated by a thin nonmagnetic metal or insulator, the electrical resistance of this arrangement depends strongly on the relative orientations of the magnetizations of the two ferromagnets. Usually, the resistance in parallel arrangement (Rp) is much smaller than in the antiparallel one (Rap). The amplitude of the effect is then defined as (Rap- Rp)/ Rp .
As sketched, different dependencies of the resistance on the external field can be realized by tailoring the layer sequence and the lithographic shape of the film stacks. Whereas the linear dependence is appropriate for quantitative measurements of the external field, the hysteretic one can serve either for counting or for data storage.
With these thin film system, a variety of new products can be developed:
* Magnetic Sensors with high sensitivity to detect ultrasmall magnetic fields
* Sensor arrays for magnetic cameras to scan information in, e.g., security systems for product control
* Sensors for magnetoresistive Biochips capable to detect small concentrations of, e.g., antibodies, DNA sequences or proteins.
* Non volatile Random Access Memories and field programmable magnetic logic gates
We offer collaborative projects for the development of new custom-tailored sensors, storage devices and logic circuits.
Additionally, Systems On Chip (SOI's) can be realized, where, e.g. sensors and storage cells are integrated on one chip.
Our equipment allows for:
The development can be organized in direct contracts or within funded projects.
Interested in developing new products?
send an e-mail to: Günter Reiss (reiss@physik.uni-bielefeld.de)
or
contact by phone or regular mail:
Prof. Dr. Günter Reiss
Bielefeld University, Physics Department
P.O. Box 100 131, 33501 Bielefeld, Germany
Phone: +49 (0)521 106 5411, Fax: +49 (0)521 106 6046