Peter GRUENBERG

Institut fur Festkorperforschung, Forschungszentrum Julich GmbH, Germany

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Title: Spintronics and its applications

Due to the discovery of the Giant Magnetoresistance (GMR) effect in 1988, in subsequent years readable storage capacity of hard disk drives (HDD) could be increased by approximately a factor of 100. This remained not the only application in this new field, sometimes also called spintronics. In conjunction with a permanent magnet attached to a moving part it can be used to sense its position speed or rotation. This principle can be applied in macroscopic systems such as traffic as well as on the micro- and nano scale for the detection of biomolecules. Progress in GMR soon also stimulated new efforts in tunnel magnetoresistance (TMR) with the result that TMR effects of the order of 500% have been observed (as compared to only 20% in equivalent GMR structures). They are now also used in HDDs and challenge GMR. In GMR magnetic alignment in these layered structures has an effect on electrical resistivity. There is also an inverse effect to this called "Current Induced Magnetic Switching" where spinpolarized currents have an impact on magnetic order. The possibility of using this in magnetic data storage is obvious.