Open AccessMagnetic field microscopy of rock samples using a giant magnetoresistance–based scanning magnetometer
Author(s) -
Hankard Fatim,
Gattacceca Jérôme,
Fermon Claude,
PannetierLecoeur Myriam,
Langlais Benoit,
Quesnel Yoann,
Rochette Pierre,
McEnroe Suzanne A.
Publication year - 2009
Publication title -
geochemistry, geophysics, geosystems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.928
H-Index - 136
ISSN - 1525-2027
DOI - 10.1029/2009gc002750
Subject(s) - magnetometer , microscope , materials science , magnetic field , giant magnetoresistance , resolution (logic) , image resolution , noise (video) , microscopy , magnetic force microscope , magnetoresistance , scanning hall probe microscope , optics , nuclear magnetic resonance , scanning electron microscope , physics , magnetization , conventional transmission electron microscope , scanning transmission electron microscopy , image (mathematics) , quantum mechanics , artificial intelligence , computer science
We have developed a new scanning magnetic microscope to image with micrometric resolution magnetic fields originating from room temperature polished samples. This microscope is based on a giant magnetoresistance (GMR) sensor working at room temperature. These magnetic sensors are sensitive to the in‐plane components of the magnetic field. The size of the sensing element is 9 μ m × 36 μ m. The noise of the GMR sensor is dominated by a low‐frequency 1/f noise. The field equivalent noise of the sensors is 10 nT at 1Hz and decreases to 0.3 nT above 1 kHz for a 1 mA sensing current. The spatial resolution of the system is ∼20 μ m, and its peak‐to‐peak noise during operation is ∼250 nT. Its high spatial resolution and a minimum sensor‐to‐sample distance of 30 μ m compensate for its rather moderate field sensitivity. This room temperature small‐sized and rugged magnetic microscope appears as a powerful instrument for small‐scale rock magnetic investigations.