C h a p t e r 6 | A D M T 4 0 0 0 D e s i g n , I m p l e m e n t a t i o n , a n d A p p l i c a t i o n s
As a magnet rotates in front of the domain wall
generator, the magnetic lines align with the magnet's
direction due to low shape anisotropy. However, in
the narrow nanowire, the magnetization direction is
restricted to either parallel or anti-parallel because
of its nanometer-scale geometry. When the magnet
rotates 180 degrees, a domain wall forms at the
entrance of the nanowire and propagates through it,
altering the magnetization direction in the narrow strip.
This change in magnetization direction is detected
using a GMR (Giant Magnetoresistance) process,
where the resistance value shifts with the magnetic
field direction. The GMR structure includes a pinned
layer at the base and a top layer that moves with the
magnetic field direction.
The ADMT4000 sensor features a 46-turn spiral
design, consisting of 23 turns on the left side
extending from the center outwards and another 23
turns on the right side retracting from the outside
inwards. However, the next-generation part aims to
increase the turn count more than fivefold, enhancing
the sensor's capabilities and addressing the growing
demands of the market.
18
Engineering Reliable Industrial Automation With Sensor Fusion
