Computer memory speed increased a thousandfold

Engineers at the University of California San Diego have achieved a breakthrough in controlling the magnetic states of a material — they have learned to switch them simply by changing the shape and focus of a laser beam. This approach has the potential to fundamentally change the principles of data recording, making it many times faster and denser. The results of the study have been published in the journal Nature Communications.

In modern magnetic storage devices, information is stored in tiny regions with different magnetization directions — these are what encode digital zeros and ones. Traditionally, an external magnetic field is used to switch between states, but scientists are increasingly seeking ways to replace it with light pulses.

The researchers worked with multilayer structures made of platinum and cobalt. Instead of experimenting with the material's composition, they took a different path — they focused on the properties of the light itself: the polarization distribution within the beam and its focusing. This approach allowed them to precisely control heating and selectively influence magnetization.

The team demonstrated that a specially shaped beam can trigger fundamentally different switching modes. In one of them, the development of the magnetic domain is determined by the direction of light polarization rotation, while in another, the magnetization reversal occurs without such a dependency. And all of this — without an external magnetic field.

During the experiments, a sequence of ultrashort pulses created a small region with opposite magnetization and then gradually expanded it. The scientists also managed to achieve switching in a thicker structure than previous experiments of this type had allowed. This discovery is of key importance for developing materials capable of reliably retaining recorded information.

According to the researchers' estimates, optical switching could potentially work more than a thousand times faster than methods based on external magnetic fields. However, this refers to the theoretical potential of the technology — the team has not yet created a finished storage device with such acceleration.

Before practical application, a number of serious engineering challenges still need to be solved. The ultrafast laser used cannot yet be integrated into a computer chip. The authors plan to reduce the affected area to a few hundred nanometers and to find combinations of materials and light sources better suited for compact electronics.