Magnetic Control of Ultrafast Demagnetization in 2D Ferromagnets Revealed

A groundbreaking study led by Professor Sheng Zhigao at the Hefei Institutes of Physical Science, part of the Chinese Academy of Sciences, has unveiled significant advancements in the control of ultrafast spin dynamics within two-dimensional (2D) van der Waals ferromagnets. Collaborating with Professor A.V. Kimel from Radboud University, the research team demonstrated that strong magnetic fields can effectively modulate laser-induced ultrafast demagnetization processes. This research, published in the National Science Review on June 17, 2025, has profound implications for the future of spintronics and information technology.

The study primarily focused on Fe₃GeTe₂, a 2D ferromagnet recognized for its unique layered structure and potential applications in spintronic devices. Utilizing the Steady High Magnetic Field Experimental Facility, the researchers employed time-resolved magneto-optical Kerr effect spectroscopy to examine the dynamic spin behavior in this material. Their findings revealed that a magnetic field of 7 tesla could accelerate the demagnetization process by as much as 60%, while simultaneously suppressing the efficiency of demagnetization by 34%. This dual action was unprecedented, as previous investigations largely concentrated on the intrinsic properties of materials or the characteristics of laser pulses, neglecting the influential role of external magnetic fields.

Professor Zhigao explained, "Our research highlights the critical impact of magnetic fields in regulating spin dynamics. This insight opens new avenues for harnessing ultrafast demagnetization in various magnetic materials beyond those studied traditionally."

The mechanism proposed by the researchers is based on spin entropy variations articulated through the well-established three-temperature model, which offers a more universal explanation for the observed phenomena. Unlike other mechanisms that are specific to individual materials, this model suggests that the effects of magnetic fields on ultrafast demagnetization could be applicable to a wide range of magnetic materials, which could revolutionize the development of faster data processing technologies.

Interestingly, the regulatory effects of the magnetic field were found to be more pronounced at temperatures around 200 K, indicating potential real-world applications in high-speed magnetic storage and logic devices operating near room temperature. This finding aligns with the increasing interest in developing spintronic devices that leverage ultrafast spin dynamics for improved performance in data storage and processing tasks.

The implications of this study extend beyond the specific material examined. The ability to control ultrafast demagnetization through magnetic fields could lead to significant advancements in spintronics, with potential applications in next-generation computing technologies. As the field of spintronics continues to evolve, understanding the interplay between magnetic fields and spin dynamics will be crucial for the development of high-speed, efficient devices.

In conclusion, this research not only advances the fundamental understanding of spin dynamics in 2D ferromagnets but also sets the stage for future innovations in magnetic storage and logic devices. The results underscore the importance of interdisciplinary collaboration in pushing the boundaries of materials science and technology. As the world moves towards increasingly data-intensive applications, such advancements in spintronics could play a pivotal role in shaping the future of information technology.