Conventional magnetoresistance has been known for a number of years, since
early low temperature solid state materials research started. When a magnetic
field is applied to certain materials their resistance changes -
Magnetoresistance. This effect is of a small percentage and was typically
observed at very low temperatures.
Giant magnetoresistance was first discovered in 1987 by Fert, Grünberg, and Parkin. Unlike magnetoresistance, the percentage change in resistance was found to be quite large, and giant magnetoresistance was soon found in certain materials at room temperature. I measured the noise associated with giant magnetoresistance materials -- which is important since noisy materials would not be very useful for technological application. GMR offers a way in which magnetic fields may be detected merely by measuring the resistance of GMR materials; and blocks or stripes of these materials may be made quite small. Examples of devices using such small magnetic detectors might be:
How do hard drives work? See Quantum Corporation's description.
Alison Chaiken's Magnetoresistance Links
What units are used to measure magnetic fields?
Leif's GMR publications Page
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