Magnetization can be switched using a single laser pulse, but it remains unclear whether the underlying microscopic process can be scaled down to the nanometer level, a necessary step for this technology to be viable in future data storage applications.
Researchers at the Max Born Institute in Berlin, Germany, in collaboration with colleagues at the Instituto de Ciencia de Materiales in Madrid, Spain, and the free-electron laser facility FERMI in Trieste, Italy, have determined a fundamental spatial limit for light-driven magnetization reversal.
Modern magnetic hard drives can store more than one terabit of data per square inch, which means that the smallest unit of information can be encoded on an area smaller than 25 nanometers by 25 nanometers. In laser-based, all-optical switching (AOS), magnetically encoded bits are switched between their “0” and “1” state with a single ultrashort laser pulse.
To realize the full potential of AOS, particularly in terms of faster write/erase cycles and improved power efficiency, we thus need to understand whether a magnetic bit can still be all-optically reversed if its size is on the nanometer-scale.
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