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The Defense Intelligence Agency's Defense Warning Office issued this Defense Intelligence Reference Document, dated 23 March 2010, as one of a series of advanced technology reports produced in FY 2009 under its Advanced Aerospace Weapon System Applications Program. The report reviews metallic spintronics, including giant magnetoresistance, spin-transfer-torque and antiferromagnetic spintronics, along with their applications. It concludes that spintronic devices could offer radiation-resistant, low-power electronics suited to aerospace use and long space trips.
From the source: Release of 2026-09-18 Incident: 3/23/10, Las Vegas, Nevada. Released with redactions. This document is a Defense Intelligence Reference Document (DIRD), a technical reference format used by the Defense Intelligence Agency (DIA) to capture baseline knowledge on a specific topic for later analytic use. DIRDs are best understood as reference and synthesis products rather than as original research. It is one of 38 DIRDs produced under the Advanced Aerospace Weapon System Applications Program (AAWSAP) between 2009 and 2011. Because AAWSAP’s scope permitted a broad range of supporting topics, not every DIRD in the series directly concerns aerospace systems or future threat assessment. The following summary reflects the DIRD’s scope and framing at the time of writing and should not be read as implying current validation of the concepts discussed. This DIRD surveys metallic spintronics, a branch of electronics that seeks to use both the electric charge and the magnetic spin of electrons to store, detect, and manipulate information, and argues that the field could lead to faster, lower-power, and more radiation-resistant devices than conventional semiconductor electronics. The report focuses on two main effects: giant magnetoresistance (GMR), which allows magnetic states to be read through changes in electrical resistance, and spin-transfer torque (STT), which allows electrical currents to change those magnetic states. The DIRD reviews their underlying physics, the experimental work then available, and possible applications in memory, sensors, oscillators, and logic devices. The document treats metallic spintronics as a promising field while emphasizing that many of its more advanced proposed applications still require substantial further development.
UNCLASSIFIED/ /fOft Offl@IAL W&E 8,.Llf pulses (STT switching). Figure 9 shows scanning transmission x-ray microscopy (Reference 53) images of in-plane components of magnetization M - Mx in panel (a) and My in panel (b)-in the free Cafe layer (indicated by blue ellipse) of a 100x150-nm 2 magnetic nanopillar. The images were obtained by scanning a focused (diameter~ 30 nm) circularly polarized x-ray beam across the CoFe layer, with the photon energy tuned to the characteristic Co L3 resonance to provide magnetic contrast through the x ray magnetic circular dichroism effect (Reference 54 ), and by monitoring transmission of the x-rays as a function of the position x, y with a fast avalanche detector. The M vector field of the free layer can be reconstructed from the measured Mx and My components as illustrated in Figure 9c, and the ultrafast x-ray microscopy technique provided a means to monitor this field as a function of time with ~ 100-picosond resolution . The spatial resolution of the technique is set by the spot size of the x-ray beam (~30 nm) and currently limits its application to spintronic devices > 100 nm in size (Reference 52). Potentially, however, technical development of the ultrafast x-ray microscopy may lead to an ultimate technique for STT studies that can probe the M vector field on the nanometer length scale with picosecond time resolution. (a) (b) (c) Figure 9. Scanning transmission x-ray microscopy images of Mx (a) and Mv (b) components of magnetization M combine into the vector field (c), which represents the direction of Min the plane of the CoFe free layer. (Reference 52) 3 .3 STT APPLICATIONS The STT method to manipulate magnetic moments by an electrical current offers unprecedented spatial and temporal control of spin distributions and attracts considerable attention because of its potential application in a broad range of technologies. The perspective of STT for GHz communication applications and in magnetic recording technology is discussed. The STT application in high-frequency technologies is based on the spin-transfer induced precess ion of spins . The previous section discussed how precession of magnetization in GMR devices ca n convert a de current input into an ac voltag e output. The frequency of this output can be tuned from a few GHz to > 100 GHz by changing the applied magnetic field and/or the de current, effectively resulting in a current controlled oscillator for use in practical microwave circuits. Hence, the STT effect in UNCLASSIFIED/ /FOR OFFIGl.t.k Wii QNk¥ 10
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Official release, from the pursue collection. The PDF is mirrored here; the original link is above. 27 pages are in the text index: search them above, or from the library's search.