A research team has taken a major step forward in the field of spintronics, a technology that uses not only the charge but also the spin of electrons to create faster, smarter, and more energy-efficient electronic devices. Their discovery could pave the way for the next generation of memory chips that combine high speed with low power consumption.
In spintronic memory, information is stored using tiny magnetic regions called magnetic domains. A magnetic domain with its magnetic moments pointing upward represents a "1," while one pointing downward represents a "0." Data can be read or written by shifting these domains with an electric current. The boundaries between them, known as domain walls, play a crucial role, as moving domains means moving these walls. Achieving fast and efficient domain wall motion is essential for developing advanced memories such as magnetic shift registers and three-terminal magnetic random access memories (MRAM).
The researchers focused on an artificial antiferromagnetic thin film made of cobalt (Co), iridium (Ir), and platinum (Pt) layers. This carefully engineered structure, in which two Co layers are separated by an Ir layer and sandwiched between Pt layers, makes the two Co layers aligned in opposite directions - an arrangement known as antiferromagnetic coupling. The Pt layers help drive motion in the material through a phenomenon called the spin Hall effect, which generates streams of electron spins that push on the magnetic moments in the Co layers.
At first glance, it might seem that the spins generated from the top and bottom Pt layers would cancel each other out because they have opposite orientations. However, the team discovered that these opposing forces actually combine in a unique way, working together to move the domain walls instead of stopping them. This dual-torque mechanism was confirmed through both experiments and numerical simulations, marking the first demonstration of this type of spin-driven motion in such a material.
The researchers went a step further by introducing a subtle gradient in the thickness of the Co layers, breaking the structure's symmetry. This created an additional effective magnetic field that made it even easier to move the domain walls. As this field increased, less current was needed to drive the motion, and the walls moved faster, allowing for information to be processed more efficiently.
The findings open up new possibilities for energy-saving, high-speed spintronic memory devices. Technologies like magnetic domain wall memory and three-terminal MRAM, which use this type of domain wall motion, could play a key role in the digital infrastructure that supports artificial intelligence and the Internet of Things.
"Our results show a new way to control domain wall motion using combined spin torques in an artificial antiferromagnet," said the research team. "This discovery could bring us closer to creating next-generation spintronic devices that are faster and consume far less energy than today's electronics," said Takeshi Seki, a professor at the Institute for Materials Research at Tohoku University, and co-author of the paper.
While spintronics has traditionally relied on ferromagnetic materials, antiferromagnetic spintronics is now emerging as a promising frontier, offering the potential for greater miniaturization and higher operation speeds. The team's demonstration of current-induced domain wall motion in an artificial antiferromagnetic structure marks an important milestone toward that goal. Moving forward, they aim to fine-tune the effective magnetic fields that control this motion, unlocking even higher performance and pushing spintronic technology into a new era.
Details of the researchers' breakthrough was published in the journal Advanced Science on October 17, 2025.
- Publication Details:
Title: Efficient Manipulation of Magnetic Domain Wall by Dual Spin-Orbit Torque in Synthetic Antiferromagnets
Authors: Hiroto Masuda, Yuta Yamane, Takaaki Dohi, Takumi Yamazaki, Rajkumar Modak, Ken-ichi Uchida, Jun'ichi Ieda, Mathias Kläui, Koki Takanashi, and Takeshi Seki
Journal: Advanced Science
