Magnetic diode
The magnetic diode is a diode whose resistance value can be changed by an external magnetic field .
It is based on a special magnetoresistive effect that differs from the Hall effect and the effects in ferromagnetic layers.
construction
Magnetic diodes are germanium semiconductor components. An n-zone is doped into one end of a germanium cuboid and a p-zone is doped into the other end. In between there is a relatively large undoped zone. (see also pin diode ) This zone has a very low conductivity (intrinsic conductivity, i-conductivity). One edge of this zone is so contaminated that a so-called recombination zone (R zone) is created there. This R-Zone "swallows" charge carriers . The finished cuboid is now provided with contacts and placed in a housing. Often two diode bodies come in one housing, since magnetic diodes are often used as double diodes.
function
When a magnetic field acts on the magnetic diode , the electrons , depending on the polarity of the field, are pushed towards or away from the R zone due to the Lorentz force . Charge carriers that get into the R-zone are "swallowed" by it and thereby cause a lack of electrons. This lack of electrons creates a high-resistance barrier layer. The recombination, and thus also the change in resistance, is controlled via the magnetic flux density B. The higher the field, the more electrons disappear. This results in an increase in resistance.
Magnetic diodes are very temperature dependent.
Applications
- Speed measurement
Manufacturers and models
- Telefunken magnetic diode AHY 10
Individual evidence
- ↑ Herbert Tholl: Components of semiconductor electronics. Springer-Verlag, 2013, ISBN 978-3-322-92762-0 , p. 277 ( limited preview in the Google book search).