To store larger amounts of data on ever smaller hard drives, researchers are trying to design ever smaller magnetic bits and bytes. In Switzerland, scientists of the Paul Scherrer Institute (PSI) are currently working with a surface made up of tiny squares of only thousandths of a millimetre. Each of these is a magnet – which means it has the potential to become a memory bit. The trick of the PSI research, however, lies in the nature of the switching.
In contrast to conventional hard drives, where the switching is done with a small magnetic head, the Swiss researchers flip the magnetic polarity of the squares with a laser beam. In earlier attempts the researchers showed that a short, intense laser pulse can switch micro-magnets hundreds of times faster than a magnetic head. That procedure also takes less energy and is therefore less expensive.
However, the behaviour of the magnetic squares under laser light is still far from being fully understood. The most recent series of tests therefore focused on understanding the flips in polarity in shots of billionths of a second. It turned out that a laser beam that simultaneously irradiates many squares does not reverse the magnetization of all of them. Rather, sub-structures are created within the illuminated squares. PSI will continue to pursue these connections in an effort to make the most of these enormous switching speeds of less than 100 billionths of a second for future developments.