Mars
Pathfinder Lander (MPL) carried an instrument package called the Magnetic
Properties Experiment.
The main goal was to define the saturation magnetization of the
particles sticking to the various magnets on Mars
and if possible to identify minerals responsible for the magnetization
of the dust. The fact that four of magnets have
captured dust required that the collected particles have an average
saturation magnetization (Is) of about 4 Am*2/kg.
Considering that material on magnet 4 may have Is= 20 Am*2/kg
(see fig below) Pederson et al (1998) concluded that maghemite
(it's Is=70Am*2/kg) could be responsible for such high magnetization.
Apparently microscopic hematite with Is=0.4Am*2/kg
can not be responsible for the magnetization of the airborne dust.
Magnetization curves for bulk sample and for dust on magnets 2 and 4.
The saturation magnetization of bulk sample, dust on magnet 2
and dust on magnet 4 =
5Am*2/kg, 10Am*2/kg, and 17Am*2/kg correspondingly (Pederson
et al, 1998)
http://mars.jpl.nasa.gov/MPF/science/magnetic.html
http://calspace.ucsd.edu/marsnow/library/science/geological_history/magnetic_fields1.html
http://ntserv.fys.ku.dk/mars/old/folder/folder.htm
http://www.sciencemag.org/cgi/content/full/278/5344/1768
