As artificial intelligence, cloud computing and digital services continue to expand, the world is facing a growing need for faster and more energy-efficient ways to store and process information. A team led by the National Institutes for Quantum Science and Technology (QST) has now developed a new magnetic memory material that can be rewritten using laser light instead of electric current, a step that could help reduce power consumption in data centers and support future high-speed information systems. This study was published online in Applied Physics Letters on June 8, 2026 (DOI: 10.1063/5.0328535).
The new material allows magnetic information to be switched by a single ultrashort laser pulse. Because light can reverse magnetic states much faster than electric current, the approach could deliver switching speeds roughly 1,000 times higher than those of conventional electrically driven magnetic memory, while also reducing heat generation and energy loss. The researchers say the advance points to a new class of low-power magnetic memory for AI hardware, edge devices and future optoelectronic platforms.
"Today's digital society needs memory technologies that are both faster and more sustainable," said Dr. Seiji Sakai, Group Leader at the Quantum Materials and Applications Research Center, Takasaki Institute for Advanced Quantum Science, QST. "By showing that a practical memory material can be switched using light, we believe this work opens a realistic path toward ultrafast, low-power devices for future information systems."
Magnetic memory stores information by changing the direction of magnetization inside a material. Existing magnetic memory technologies typically use electric current to write data. That approach is attractive because it can retain information even when power is turned off, but it also faces major limitations: writing speed is constrained, and current generates heat, which increases energy consumption. Those challenges are becoming more serious as AI and large-scale digital infrastructure continue to push power demand upward.
To address this problem, the team focused on all-optical switching, a phenomenon in which light reverses magnetic orientation without the need for current. This effect had previously been observed in ferrimagnetic materials, but those materials were not suitable for practical memory because their magnetic readout properties were too weak for stable digital operation. By contrast, the alloy CoFeB is already widely used in magnetic memory because it offers nearly complete spin polarization and excellent readout performance, yet it had not been considered suitable for optical switching.
The researchers overcame that barrier by designing a new artificial ferrimagnet built from antiferromagnetically exchange-coupled layers of cobalt, gadolinium and CoFeB. By tuning the thickness of each layer with atomic-scale precision and optimizing the full multilayer structure, they created a material in which magnetic states can be reversed reproducibly with a single femtosecond laser pulse. The team also showed that the write-and-rewrite operation could be repeated stably, demonstrating the basic functionality required for memory applications.
"One of the most important aspects of this work is that we achieved optical switching in a CoFeB-based system, which is already highly compatible with magnetic tunnel junction technology," Sakai said. "That compatibility makes this result much more relevant for future devices than earlier demonstrations limited to model materials."
A key part of the study was the use of NanoTerasu, Japan's fourth-generation synchrotron radiation facility, where the team analyzed spin arrangements and interlayer interactions in the material using X-ray magnetic circular dichroism spectroscopy. These measurements provided atomic-level insight into the multilayer structure and played an essential role in guiding the design of the new material. The submission materials note that the ferrimagnets were developed using synchrotron analysis at NanoTerasu.
The potential impact of the work extends beyond laboratory demonstration. Faster, lower-power memory could help tackle one of the major hidden costs of the AI era: the rapidly increasing electricity demand of data centers and advanced computing systems. According to the submission materials, the technology may also serve in the longer term as a photoelectric conversion interface linking optical interconnects and electronic circuits, eventually contributing to integrated chips that combine photonics and electronics on the same platform. Practical use of such materials in optoelectronic interfaces could begin within the next decade.
About National Institutes for Quantum Science and Technology, Japan
The National Institutes for Quantum Science and Technology (QST) was established in April 2016 to promote quantum science and technology in a comprehensive and integrated manner. The new organization was formed from the merger of the National Institute of Radiological Sciences (NIRS) with certain operations that were previously undertaken by the Japan Atomic Energy Agency (JAEA).
QST is committed to advancing quantum science and technology, creating world-leading research and development platforms, and exploring new fields, thereby achieving significant academic, social, and economic impacts.
About Dr. Seiji Sakai
Dr. Seiji Sakai is a researcher at the Quantum Materials and Applications Research Center of QST. He focuses his research on magnetic and spin-electronic low-dimensional materials and their device applications. He has published over 130 papers on these topics, which have received more than 1,700 citations. Dr. Sakai is currently working on developing integrated spintronics and nanophotonics technologies to advance optoelectronic integration for next-generation information systems.
Reference
DOI: http://doi.org/10.1063/5.0328535
