Applied Physics

Tracking Gyrating Memories

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Science  23 May 2008:
Vol. 320, Issue 5879, pp. 987
DOI: 10.1126/science.320.5879.987b

Whereas the bits in present magnetic memory storage media are written using electrical current pulses in a write head, recent work has shown that the spin-polarized current in a ferromagnetic medium can impart a spin-transfer torque to the magnetization, resulting in its motion. Such a wired-up memory architecture would allow yet higher storage density and provide faster access times than present hard drives offer. Understanding how the spin current affects the dynamics will help in developing memory storage devices based on this effect. Bolte et al. provide a direct view of the dynamics of the process. They use time-resolved x-ray imaging to track the motion of the magnetization, showing how magnetic vortices in permalloy dots gyrate and jiggle in response to the injected spin-polarized current. The technique is sufficiently sensitive to uncover the various contributions to the dynamics, thereby offering the opportunity to fine-tune the process. — ISO

Phys. Rev. Lett. 100, 176601 (2008).

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