The 21st century digital economy and technology is presently facing fundamental scaling limits (heating and the superparamagnetic limit) as well as societal challenges: the move to mobile devices and the increasing demand of cloud storage leads to an enormous increase in energy consumption of our ICT infrastructure. These developments require new strategies and paradigm shifts, such as photon- and spin-based technologies. Since the demonstration of magnetization reversal by a single 40 femtosecond laser pulse, the manipulation of spins by ultra-short laser pulses has become a fundamentally challenging topic with a potentially high impact for future spintronics, data storage and quantum computation. The ability to control the macroscopic magnetic ordering by means of femtosecond laser pulses provides an alternative and energy efficient approach to magnetic recording. The realization that femtosecond laser induced all-optical switching (AOS) as observed in ferrimagnets exploits the exchange interaction between their sub-lattices, has opened the way to engineer new and rare-earth-free magnetic materials for AOS. Expansion to hybrid magnetic materials, multilayers, FePt and even magnetic garnets are ongoing efforts to expand AOS to future magnetic recording media technology. Recent developments using plasmonic antennas indicate the possibility to even scale the technique of AOS to the nanoscale, making AOS a potential candidate for fast and energy efficient data storage.
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