- Collaborative effort by Professors Lee Kyung-jin and Kim Gap-jin of KAIST and Professor Jeong Myung-hwa of Sogang University overcomes previous limitations by observing quantum mechanical spin pumping at room temperature, paving the way for advancements in next-generation electronic devices



The Ministry of Science and ICT (Minister Yoo Sang-im, hereinafter referred to as 'MSIT') announced that a joint research team, led by Professors Lee Kyung-jin and Kim Gap-jin from the Korea Advanced Institute of Science and Technology (KAIST) and Professor Jeong Myung-hwa from Sogang University, has, for the first time globally, observed quantum mechanical spin pumping at room temperature.



Supported by MSIT's Basic Research Project (Mid-sized Research and Basic Research Laboratory), this significant achievement was published in the international journal ‘Nature’ on January 30 (local time, January 29, 4 PM GMT).*

*Title of the paper: "Signatures of Longitudinal Spin Pumping in a Magnetic Phase Transition"



Electrons possess both an electric property—charge—and a magnetic property known as spin*. The movement of electrons within a material generates an electric current, which can be categorized into charge current (caused by the movement of electric charge) and spin current (resulting from the flow of electron spins).

* Electron Spin (Spin Angular Momentum): The intrinsic quantum angular momentum of electrons



Most electronic devices we use today operate through charge currents. However, as electrons flow, they inevitably collide with atoms within the material, generating heat. This leads to increased energy consumption and reduced efficiency.



To address these issues, researchers worldwide have been exploring the development of electronic devices that utilize spin current instead of charge current—a field known as spintronics.



The key to realizing spintronics technology lies in generating spin current. Among various methods, spin pumping is one of the primary techniques.



Spin pumping refers to the phenomenon where spins transfer from a ferromagnet to a non-magnetic material due to precession* (the wobbling motion of the spin axis). However, spin currents generated through classical mechanics have been too weak for practical application in electronic devices.

*Precession: A motion observed when the axis of a spinning object, like a top, wobbles as it rotates



In 2019, Professor Jeong Myung-hwa’s research team published findings on spin interactions in magnetic thin films in the renowned materials science journal ‘Nature Materials’.* Since then, the team has continued related studies, progressively developing techniques for fabricating magnetic thin films.

*Title of the paper: Long-range chiral exchange interaction in synthetic antiferromagnets



Building on these techniques, Professor Jung’s team successfully fabricated high-quality iron (Fe)-rhodium (Rh) magnetic thin films. By leveraging the unique properties of these films in collaboration with Professor Kim Gap-jin’s team, they observed a significantly large spin current. Professor Lee Kyung-jin’s team further analyzed the phenomenon through quantum mechanical theory and validated the findings with additional experiments.



Notably, while most quantum mechanical phenomena are observable only at extremely low temperatures, this research is highly significant because it demonstrates quantum mechanical spin pumping at room temperature. Furthermore, the study introduces a method that generates more than ten times the spin current compared to traditional classical approaches, paving the way for advancements in next-generation electronic devices.



In addition, the research holds great value as an exemplary case of collaborative basic research. The joint efforts enabled the expansion of studies from static spin states to dynamic spin states during magnetic transitions, leading to world-class achievements.



The joint research team stated, "While conventional spintronics research has relied on classical spin dynamics, this study is significant because it demonstrates the effectiveness of utilizing the quantum properties of spin, offering superior potential for practical applications."





For further information, please contact the Public Relations Division (Phone: +82-44-202-4034, E-mail: msitmedia@korea.kr) of the Ministry of Science and ICT.



Please refer to the attached PDF.