Researchers at the University of California, San Diego, have developed a method to switch material magnetization using shaped laser pulses. This approach aims to advance the development of magnetic memory by improving speed, energy efficiency, and device size.
The team utilizes an ultrafast laser to focus energy on a small surface area. By reducing the laser spot size to under 1.36 micrometers, they can switch magnetization direction independently of the light's polarization helicity.
The experiment involved a structure consisting of nine alternating layers of platinum and cobalt. This exceeds previous limitations, where optical switching was typically restricted to structures with a maximum of three magnetic layers.
The switching process relies on a sequence of pulses rather than a single burst. The initial pulse heats the material to create a small region of reversed magnetization, while subsequent pulses expand this area until the material reaches a new stable state.
By adjusting the laser spot size and shape, researchers control the local heating and forces applied to the magnetic structure. The team estimates this method could be over 1,000 times faster than techniques using external magnetic fields.
