AAWSAP DIRD, Metallic Spintronics, March 2010

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Spintronics is a broad research field with (currently) three major
subfields: (1) materials research that is attempting to create new
materials that are both magnetic and semiconductors, (2) research
on novel magnetotransport effects in ferromagnetic metals, and (3)
research on techniques that can be used to manipulate individual
electron spins. The first subfield is targeting magnetic
semiconductors because devices based on such materials would be
the easiest to integrate with the present semiconductor device
technology and processing capabilities. However, despite extensive
research, most semiconductor spintronic devices are still theoretical
concepts awaiting experimental demonstrations. This report focuses
on spintronics research in metallic systems within the scope of the
second and third subfields. The second subfield has experienced an
unprecedented period of new discovery over the past 20 years,
including the discovery of GMR, and has already spawned major
technological change in the information storage industry with the
use of GMR sensors and read heads. The third subfield is vital for
spintronic devices, as virtually any processing of information in such
devices is associated with transport and manipulation of spins.
New and efficient methods for manipulating spins that stimulate
active research programs in spintronics at a large number of
academic institutions and a half-dozen industrial research labs
around the world are highly desirable. The prize to be gained is
active control and manipulation of spin distributions (magnetic
moments) for new and improved functionality in
electronic/spintronic devices. The confluence of intense basic
science and industry interest in ferromagnetic metal spintronics has
not occurred on this scale in physics in a long time.
The report is arranged as follows: Section 2 is dedicated to
magnetotransport effects in magnetic systems where magnetic
configuration can influence the system's transport properties. It
discusses GMR in magnetic multilayers and related phenomena,
highlights basic physical principles responsible for GMR, and
describes technological applications of the effect. Section 3 focuses
on the reverse connection between the system's magnetic
configuration and its transport properties-the so-called STT effect.
The physical origin and potential applications are discussed. Section
4 discusses other new directions in metallic spintronics, with a
particular focus on spintronics with antiferromagnetic materials.
Section 5 summarizes, with an eye to the future, the development of
spintronic technologies and their aerospace applications.
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