1 EXCHANGE BIAS, GIANT MAGNETORESISTANCE, TUNNEL MAGNETORESISTANCE AND MAGNETIC RANDOM ACCESS MEMORIES

The study of electrical transport in magnetic materials has a long history. However, since the discovery in 1988 of the so-called giant magnetoresistance (GMR) in metallic multilayers [1], the subject has generated a great deal of interest. This was important not only from the basic research point of view but also from the applied research point of view. In 1997 IBM introduced in the hard-disk technology magnetoresistive read heads based on the GMR effect, which has allowed the increase in the density of the stored information in hard disks at a rate much beyond previous technologies [2]. GMR can be considered to be the first paradigm of the so-called Spin Electronics, where, in sharp contrast with semiconductor technology, the spin as well as the charge transport is taken into account. This field could be developed thanks to the fine nanometric control of thin films in the growth direction. Figure 1. Original figure included in reference [1], where the GMR effect was first reporte