Applied Physics

Stabilizing Miniaturized Memories

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Science  02 Mar 2001:
Vol. 291, Issue 5509, pp. 1665
DOI: 10.1126/science.291.5509.1665a

Increasing the bit density of magnetic devices by decreasing the size of the bit that is magnetically written on has yielded storage media operating at a density of about 1 gigabit per square centimeter. At higher densities and smaller bit sizes, however, the stored information on each bit, in the form of a magnetic orientation, becomes susceptible to thermally induced fluctuations and spontaneous reversals of the magnetization.

Lohau et al. report results from one possible solution in which the memory elements are patterned. Using an ion-beam, they divide a magnetic thin film of granular cobalt-chromium-platinum into an array of isolated square islands, with dimensions between 80 and 230 nm, corresponding to areal densities of 16 Gbit/cm2 and 1.6 Gbit/cm2, respectively. They find that bits with dimensions less than 130 nm comprise a single magnetic domain, can be individually addressed, and are relatively stable to thermal memory loss as compared to similar areas written to in the unpatterned region of the material. — ISO

Appl. Phys. Lett.78, 990 (2001).

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