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Progress toward terabit-rate high-density recording

September 23, 2010
American Institute of Physics
Next-generation high-density storage devices may keep more than 70 times the contents of the entire US Library of Congress on a single disc -- but only if that data can be written quickly enough. Researchers have now demonstrated a way to record onto ferromagnetic films thirty times faster than today's technologies.

Research is closing in on the next-generation of ultra-high-density magneto-optical storage devices that could store more than 6,000 Terabits (6 petabits) of data, more than 70 times the contents of the entire U.S. Library of Congress, on a single 5-inch disc. Yet the vast storage amount is limited by the ability to write data quickly enough to the device. In the Journal of Applied Physics, researchers at Sun Yat-Sen University in China have demonstrated a way to record on ferromagnetic films using a laser-assisted ultrafast magnetization reversal dynamics.

The technique uses so-called time-resolved polar Kerr spectroscopy combined with an alternating magnetic field strong enough to re-initialize the magnetization state of gadolinium-iron-cobalt (GdFeCo) thin films. Tianshu Lai and colleagues showed that the magnetization reversal could occur in a sub-nanosecond time scale, which implies that next- generation magneto-optical storage devices can not only realize higher recording densities but also ultrafast data writing of up to a gigahertz. Such speed is at least thirty times faster than that of present hard disks in computers.

Laser-assisted magnetic recording was demonstrated on a sub-picosecond time scale under a saturated external magnetic field. "We found that the rate of magnetization reversal is proportional to the external magnetic field," says Lai, "and the genuine thermo-magnetic recording should happen within several tens to hundreds of picoseconds when we apply a smaller magnetic field than the coercivity of the recording films."

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The above post is reprinted from materials provided by American Institute of Physics. Note: Materials may be edited for content and length.

Journal Reference:

  1. Zhifeng Chen, Ruixin Gao, Zixin Wang, Chudong Xu, Daxin Chen, Tianshu Lai. Field-dependent ultrafast dynamics and mechanism of magnetization reversal across ferrimagnetic compensation points in GdFeCo amorphous alloy films. Journal of Applied Physics, 2010; 108 (2): 023902 DOI: 10.1063/1.3462429

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American Institute of Physics. "Progress toward terabit-rate high-density recording." ScienceDaily. ScienceDaily, 23 September 2010. <>.
American Institute of Physics. (2010, September 23). Progress toward terabit-rate high-density recording. ScienceDaily. Retrieved May 3, 2016 from
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