25
September 2003
Applied physics: Magnets in a spin
Magnets in systems like magnetic memories are controlled using magnetic fields. But as these devices are made smaller, it gets more and more difficult to generate the strong local fields needed to make them work. The recent discovery that spin can be transferred to ferromagnets from spin-polarized currents has provided an alternative way of applying torque to small magnets that has proved particularly effective at the nanoscale. Little is known about how magnets respond to these torques, but now a technique has been developed to measure the magnetic motions that can be generated by spin transfer torques. In one mode, the constant precession of the magnet's field induced by these torques produces microwave radiation that might be used as high-frequency microwave sources or resonators for cell phones and other communications equipment.
Microwave oscillations of a nanomagnet driven
by a spin-polarized current
S. I. KISELEV, J. C. SANKEY, I. N. KRIVOROTOV, N.
C. EMLEY, R. J. SCHOELKOPF, R. A. BUHRMAN & D. C. RALPH
Nature 425, 380–383 (2003); doi:10.1038/nature01967
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Applied physics: Spintronics gets a magnetic
flute
JONATHAN SUN
Magnetic-memory devices of the future could be based on 'spintronics',
through switching the directions of electron spins. New work confirms
the physics behind a spin-switching mechanism.
Nature 425, 359–361 (2003); doi:10.1038/425359a
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