Physics: Peter Levy, NYU

Work on magnetic multilayers started in Louis Neel's laboratory in the 1960's, but it was not until one learned from the developments for the
growth of semiconductor heterostructures that one achieved in the 1980's
high quality metallic multilayers. Once this barrier was overcome, it was
apparent to Albert Fert and Peter Grunberg that one could alter the magnetic configuration in ferromagnetic metals with moderate magnetic fields,  and thereby change their resistivities. I will review the principle ideas and developments that lead to a new field that lies at the intersection between physics and technology. The steps taken by the two physicists to achieve Giant Magnetoresistance (GMR), and the differences in their seminal results, will be discussed.
While the twentieth century was dominated by advances in controlling
electrical currents through the charge of the electron, a.k.a. electronics,
the rapid developments since 1988 have lead to a control of currents
through the spin of the electron, i.e., spintronics. The groundwork for
this field comes from studies on metallic alloys and multilayers started
in the early sixties. Due to parallel developments in the growth of
semiconductor heterostructures, e.g., molecular beam epitaxy, work on
metallic layers rapidly advanced in the late seventies and early eighties.
By 1988 groups lead by Fert and GrC<nberg were able to grow metallic
multilayers which displayed the sought after effect; a small magnetic
field was able to dramatically change the electric resistance of the
structures. This lead to an immediate explosion in activity in this area;
so much so that the materials which display this effect were incorporated in the read heads of hard disk drives of computers by 1995. I will focus on developments in three distinct time periods. The first was from 1988-1995 which was dominated by metallic multilayers which displayed giant magnetoresistance (GMR), the second from 1995-2000 when reproducible magnetic tunnel junctions (MTJbs) were studied for their tunneling magnetoresistance (TMR), and the third period from 2000-2005 in which the ideas of Berger and Slonczewski were realized on the back action of currents  on the magnetic background of the materials doing the conducting,  i.e., current induced magnetization switching (CIMS). These developments  illustrate the broad range of activities in Spintronics; a field which is  barely twenty years old.