Dr. Daniel Bürgler
Giant-Magnetoresistance (GMR) describes the effect that the electrical resistivity of a structure consisting on thin magnetic and non-magnetic films ("magnetic multilayer") depends on the relative orientation of the magnetization vectors of adjacent magnetic layers. This effect was first observed in 1988 by P. Grünberg (Research Center Jülich) and A. Fert (University Paris), who in 2007 were awarded the Nobel Prize in Physics for this discovery.
The GMR effect can be used to detect magnetic fields by a change of resistivity, if the external field changes the relative orientation of the magnetic layers, e.g. from antiparallel to parallel.
Since 1998 the GMR effect is applied in high-density readheads of computer harddisks and allowed for an increase of the storage density by orders of magnitude.
The animation first explains the setup of a computer harddisk and how data is stored and retrieved. The main part presents a detailed but comprehensible picture of the GMR effect.
The animation is available as a packed file (.zip) of a QuickTime video with sound (.mov) of about 35 Mbytes. Have fun!
|Download video (35 MB)|