Thursday, November 19, 2009

Magnetic sensors

One of the most important technologies with the most important applications is the ability to detect small magnetic fields. This allows us to make more compact hard disks and more recently more sensitive detectors, including bio-detectors.

  • Gigant Magneto Resistance (GMR) is one of the important effects responsible for these technologies that exploit the difference of electrical resistivity when the current traverses two different magnetic materials (separated by a very thin non-magnetic material) and the spins of the materials are parallel or anti-parallel. Giant Magnetoresistance: The Really Big Idea Behind a Very Tiny Tool

  • The Tunnel Magnetoresistance effect (TM) , which relies in the quantum tunnel effect, is another important similar effect that can be even more sensitive. Tunnel Magnetoresistance effect
  • There transmission of light in a gas such as Rubidium can be also very sensitive to very small external magnetic fields. Laser magnetometer

A link with some of these technologies applied to sensors is
GMR for sensors

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