New Highspeed Control Strategy For Energy-Efficient Data Storage of The Future


Every year the digital data generated around the world is counted in zettabytes, or billions of millions of bytes. This data is equal to delivering data for millions of books every second. The volume of data generated is expanding continuously. All the current global electricity consumption would be devoted to data storage by 2040 if present technologies remained unchanged.  Scientists at Tohoku University and the Université de Lorraine in France reported on a new tech that drives a reduction in energy for data storage.

Data Storage scheme
A simplified representation of the high-speed and energy-efficient switching of ferromagnet operated by a single femtosecond laser pulse. The laser pulse produces a spin current by demagnetizing the ferrimagnetic layer, which moves through the nonmagnet and eventually causes the switching of the ferromagnet. The lower image elucidates an observed magneto-optical Kerr impact micrograph exposing the switching of the ferromagnetic layer. Source: Shunsuke Fukami and Stéphane Mangin

The established technology uses a high-speed laser pulse whose span is as short as 30 femtoseconds — equivalent to 0.0000000000000003 seconds. The laser pulse is implemented on a heterostructure consisting of ferromagnetic Co/Pt, ferrimagnetic GdFeCo, and nonmagnetic Cu stripes.

“Earlier study, led by a subgroup of the contemporary team. This team recognized that magnetic switching of the ferromagnetic layer after the ferrimagnetic layer had been switched.” This time, the scientists revealed the mechanism for this strange phenomenon and notice that a flow of electron spin, referred to as a spin current, following the switching of ferrimagnetic GeFeCo plays a vital role in causing the switching of ferromagnetic Co/Pt (Figure 2).

Based on this insight, they exhibited very fast and less energy-consuming switching of the ferromagnet. This was operated by a single laser pulse without switching off the ferrimagnetic layer. “This is very big news for prospective data-storage purposes as this technology can give an effective scheme to write digital data to a magnetic medium, which is currently based on a magnetic-field-induced switching,” states Shunsuke Fukami, co-author of the research.

Source: “Energy Efficient Control of Ultrafast Spin Current to Induce Single Femtosecond Pulse Switching of a Ferromagnet” by Junta Igarashi, Satoshi Iihama, Jon Gorchon, Grégory Malinowski, Michel Hehn, Quentin Remy, Julius Hohlfeld, Stéphane Mangin, Hideo Ohno, and Shunsuke Fukami.

DOI: 10.1002/advs.202001996


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