Every digital photo, document, and video saved on a hard drive is stored as a vast sequence of 1s and 0s, represented physically by tiny magnetic regions. Writing that information typically means using an external magnetic field to switch those regions between states. The process consumes substantial energy and limits how quickly data can be written.
Light can deliver energy in extremely short bursts and concentrate it into a small area, making it a promising tool for switching magnetic states. Researchers at the University of California San Diego estimate that this process, called optical switching, could be more than 1,000 times faster than approaches that rely on external magnetic fields. But making it work has meant dealing with restrictions on the magnetic material itself.
By reshaping and shrinking an ultrafast laser beam, the UC San Diego engineers have demonstrated optical switching in a stack of nine alternating layers of platinum and cobalt. Their findings, published in Nature Communications, extend the technique to a thicker structure than earlier experiments had allowed.
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