Ultrafast Lasers Signal Batman from Magnetic Hard Drive

Researchers may have unintentionally summoned Batman as they work to store larger amounts of data on smaller hard drives using lasers.

An international team has demonstrated sub-100-ps magnetization reversal inside a hard drive using femtosecond laser pulses. The hard drive stored information on 5-µm squares of gadolinium iron cobalt (GdFeCo).

“Using light for magnetic switching clearly works,” said Paul Scherrer Institute professor Dr. Frithjof Nolting.

Researchers imaged the microstructure using photo-emission electron microscopy, left, and using computer simulations, right. Courtesy of M. Fischer/Paul Scherrer Institute.

In a study published in Nature Communications (doi: 10.1038/ncomms6839), the researchers used a single laser pulse to irradiate many squares at once through refraction and interference. What resulted was a miniature magnetic substructure reminiscent of the Batman logo.

More laser light was absorbed in some areas of the squares than others, the researchers said, which prompted the magnetic switch. The laser heats the tiny magnets quickly, allowing that conversion to the opposite magnetic state.

“This could be the way to store even more data on even smaller hard drives one day,” said Dr. Loic Le Guyader of Helmholtz-Zentrum Berlin.

The work was funded by the European Union’s Seventh Framework Program, the Netherlands Organization for Scientific Research, the Dutch Foundation for Fundamental Research on Matter, the Dutch Scientific and Technical Writing group, and Japan’s Ministry of Education, Culture, Sports, Science and Technology.

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