I'm trying to understand if anisotropic magnetoresistive devices themselves (not other passive ferromagnetic components) can become magnetized, and if so, how the application of a DC 1.1 gauss field can "degauss" them.
I started with this question in electronics stackexchange, but here I'd like to understand better what is happening inside a magnetoresistive device itself.
If they themselves can become magnetized, how could a simple on-off step of 1.1 gauss "degauss" them. I'm familiar with degaussing where a much stronger, AC field is applied, and slowly and steadily ramped down in amplitude, but this is very different.
The discussion in the other question is related to the internal degaussing feature of this anisotropic magnetoresistive magnetometer:
Set/Reset and Offset Strap Drivers for Degaussing, Self Test, and Offset Compensation
and there is a short mention of the need for internal degaussing at the bottom of the second page in this FAQ:
Rotation of the sensor should vary the output voltage. If it does not, the part maybe "permed" due to strong magnetic fields over 20 gauss such as accidental proximity of magnetized tips of some hand tools during assembly. Performing the application of current pulses across the set/reset strap should degauss the sensor(s) and restore performance.
Everything is relative - in this context, 20 gauss is "strong"!
There may be some helpful background information in this presentation at magnetism.eu.
above: screenshot from the Honeywell HMC5883L datasheet, a "3-Axis Magnetoresistive Sensors and ASIC in a 3.0 x 3.0 x 0.9mm LCC Surface Mount Package."
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