UC San Diego engineers changed a magnetic material by redesigning the light aimed at it, demonstrating optical switching across nine alternating platinum and cobalt layers. The result extends a process that earlier experiments had largely confined to stacks no thicker than three magnetic layers, according to research published in Nature Communications.
Digital storage represents information through magnetic regions that point in different states, the physical equivalent of ones and zeros. Conventional writing uses an external magnetic field to flip those states. Optical switching substitutes a burst of light, potentially delivering energy faster and into a smaller target. The researchers estimate it could operate more than 1,000 times faster than field-based approaches.
The advance is not simply a brighter laser. The team shaped an ultrafast beam and concentrated it into a very small area. Initial pulses heated a tiny region enough to reverse its magnetization. Later pulses expanded that switched region until it stabilized. By controlling the beam's size and form, the group no longer needed the specific light polarization used in earlier work.
Thickness matters because a magnetic medium must retain information after it is written. UC San Diego electrical-engineering professor Abdoulaye Ndao's team worked with magnetic-materials specialist Eric Fullerton and students Muhammad Waleed Khalid and Koffi Sadzi. Their nine-layer platinum-cobalt sample showed that optical design could overcome a limit previously associated with the material stack itself.
The evidence is a laboratory demonstration, not a finished drive. The researchers repeated the experiment to test whether the unusual effect was reproducible. Publication adds peer review, but it does not establish durability over billions of write cycles, manufacturing yield, long-term error rates or energy use inside a complete storage system.
The most immediate engineering obstacle is the laser. The specialized femtosecond source used in the work cannot yet be readily integrated with computer chips. One path is to shrink the optical structure further, perhaps to a few hundred nanometers. Another is to find magnetic materials that respond similarly to laser systems that are easier to package with electronics.
The collaboration crossed two specialties that do not always share a laboratory language: Ndao's group works in optics, while Fullerton's work centers on thin-film magnetic materials and recording. That combination let the researchers alter the incoming energy instead of synthesizing an entirely new medium. It also means future progress depends on both optical confinement and material response improving together.
Density is the second promise. A narrower beam could address smaller regions, allowing more bits in the same area. That connection is plausible but conditional: the surrounding material must remain stable, heat cannot corrupt neighboring bits and the readout system must still distinguish the result. The UC San Diego release did not report a commercial partner, prototype capacity or timetable for device integration.
The study changes the research question from whether a particular thin material can switch to how carefully engineered light can control magnetism at smaller scales. That is meaningful progress in basic device physics. It should not be mistaken for a product announcement. The distance between nine switched layers on a laboratory bench and a reliable memory chip is precisely what the team's next optical and materials experiments must measure.