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Frequency Instant Jump via Magnetic Vibration... Reduces Heat Even During Gaming"
< (From left) Mujin You (Postdoctoral Researcher), Kab-Jin Kim (Professor), Albert Min Gyu Park (Research Professor) >
A new technology has been proposed that could fundamentally solve the issue of smartphones overheating during high-spec gaming or extended video streaming. Researchers at KAIST have discovered the principle of processing signals using the minute vibrations of magnets (spin waves) instead of electrons. This method significantly reduces heat generation and power consumption while enabling instantaneous frequency switching within the several GHz range. This breakthrough is expected to pave the way for smart devices with less heat and longer battery life, as well as ultra-low-power, high-speed computing.
A research team led by Professor Kab-Jin Kim from the Department of Physics announced on the 19th that they successfully achieved significant signal speed (frequency) changes at the nanoscale using spin waves—minute vibrations occurring within magnets. These vibrations are explained in units called "magnons." This achievement is being evaluated for presenting a signal control method that can drastically reduce power consumption even at extremely small scales, which was difficult to implement using conventional electron-based methods.
The material used by the research team is a Synthetic Antiferromagnet (SAF), created by stacking magnetic materials much thinner than a human hair in multiple layers. Within this structure, the spin waves manifest in two ways: acoustic mode and optic mode. The researchers were the first to identify a "mode hopping" phenomenon, where these movements suddenly switch under specific conditions.
Unlike conventional methods where signal states change continuously, this phenomenon involves a sudden shift to a completely different state at a specific moment, causing a sharp jump in frequency. This suggests a new way to control signal frequencies through the state changes of spin waves alone, without the need for complex circuits.
The core of this research is the ability to abruptly change the frequency by more than 5 GHz through this mode hopping. This effect is comparable to switching a radio channel completely with the single press of a button.
The team generated spin waves inside the magnet by sending electromagnetic signals through tiny antennas. Upon adjusting the strength of the external power and magnetic field, the vibration speed (frequency) did not change linearly but instead "jumped" suddenly. This change occurs during the "three-magnon interaction" process, where the fundamental unit of the spin wave, the magnon, either splits from one into two or merges back into one.
Notably, these rapid frequency changes are possible without complex electronic circuitry. By simply adjusting the signal intensity, the frequency can be changed freely, allowing for simpler device structures and significantly reduced power consumption.
Furthermore, this phenomenon can be used as a switch to distinguish between "on (1)" and "off (0)," making it applicable to new types of semiconductors and neuromorphic computing technology that mimics the human brain.
This research marks a significant step forward in the feasibility of "spin-wave-based information processing technology." It is expected to be utilized in various fields, including ultra-low-power computing, high-speed signal processing, and spintronic devices—a next-generation semiconductor technology that utilizes spin (magnetic properties) instead of electrons.
< Figure 1. (a) Schematic of the Synthetic Antiferromagnet (SAF) structure and the device for spin-wave propagation. Spin waves are generated and detected via a microwave antenna (CPW). (b) Optical image of the fabricated nano-device. (c) Optic magnon and (d) acoustic magnon generation and spin rotation schematics. >
< Figure 2. (a,b) Linear response showing identical spectra during magnetic field increase and decrease at low power. (c,d) Mode hopping at high power with hysteresis observed. (e–h) Quantitative results showing changes in hysteresis width according to external power. >
Professor Kab-Jin Kim stated, "This study is a case that proves we can implement and control the nonlinear dynamics of magnons—the principle of information processing using magnetic vibrations—in actual nano-devices, which had previously only been proposed in theory. It will serve as an important foundation for the development of a new information processing paradigm using spin waves instead of electrons."
Mujin You led the study as the first author, and Albert Min Gyu Park participated as the co-corresponding author. The research was published in the international academic journal Nature Communications on March 12, representing a major advancement in the field of magnon-based nonlinear dynamics.
Paper Title: Mode hopping via nonlinear magnon-magnon coupling in a synthetic antiferromagnet DOI: 10.1038/s41467-026-70298-2 Authors: Mujin You, Moojune Song, Jun Seok Seo, Donghyeon Lee, Seungha Yoon, Daiju Hayashi, Yoichi Shiota, Teruo Ono, Sanghoon Kim, Se Kwon Kim, Albert Min Gyu Park & Kab-Jin Kim
2026.04.20 View 940 -
KAIST Turns an Unprecedented Idea into Reality: Quantum Computing with Magnets
What started as an idea under KAIST’s Global Singularity Research Project—"Can we build a quantum computer using magnets?"—has now become a scientific reality. A KAIST-led international research team has successfully demonstrated a core quantum computing technology using magnetic materials (ferromagnets) for the first time in the world.
KAIST (represented by President Kwang-Hyung Lee) announced on the 6th of May that a team led by Professor Kab-Jin Kim from the Department of Physics, in collaboration with the Argonne National Laboratory and the University of Illinois Urbana-Champaign (UIUC), has developed a “photon-magnon hybrid chip” and successfully implemented real-time, multi-pulse interference using magnetic materials—marking a global first.
< Photo 1. Dr. Moojune Song (left) and Professor Kab-Jin Kim (right) of KAIST Department of Physics >
In simple terms, the researchers developed a special chip that synchronizes light and internal magnetic vibrations (magnons), enabling the transmission of phase information between distant magnets. They succeeded in observing and controlling interference between multiple signals in real time. This marks the first experimental evidence that magnets can serve as key components in quantum computing, serving as a pivotal step toward magnet-based quantum platforms.
The N and S poles of a magnet stem from the spin of electrons inside atoms. When many atoms align, their collective spin vibrations create a quantum particle known as a “magnon.”
Magnons are especially promising because of their nonreciprocal nature—they can carry information in only one direction, which makes them suitable for quantum noise isolation in compact quantum chips. They can also couple with both light and microwaves, enabling the potential for long-distance quantum communication over tens of kilometers.
Moreover, using special materials like antiferromagnets could allow quantum computers to operate at terahertz (THz) frequencies, far surpassing today’s hardware limitations, and possibly enabling room-temperature quantum computing without the need for bulky cryogenic equipment.
To build such a system, however, one must be able to transmit, measure, and control the phase information of magnons—the starting point and propagation of their waveforms—in real time. This had not been achieved until now.
< Figure 1. Superconducting Circuit-Based Magnon-Photon Hybrid System. (a) Schematic diagram of the device. A NbN superconducting resonator circuit fabricated on a silicon substrate is coupled with spherical YIG magnets (250 μm diameter), and magnons are generated and measured in real-time via a vertical antenna. (b) Photograph of the actual device. The distance between the two YIG spheres is 12 mm, a distance at which they cannot influence each other without the superconducting circuit. >
Professor Kim’s team used two tiny magnetic spheres made of Yttrium Iron Garnet (YIG) placed 12 mm apart with a superconducting resonator in between—similar to those used in quantum processors by Google and IBM. They input pulses into one magnet and successfully observed lossless transmission of magnon vibrations to the second magnet via the superconducting circuit.
They confirmed that from single nanosecond pulses to four microwave pulses, the magnon vibrations maintained their phase information and demonstrated predictable constructive or destructive interference in real time—known as coherent interference.
By adjusting the pulse frequencies and their intervals, the researchers could also freely control the interference patterns of magnons, effectively showing for the first time that electrical signals can be used to manipulate magnonic quantum states.
This work demonstrated that quantum gate operations using multiple pulses—a fundamental technique in quantum information processing—can be implemented using a hybrid system of magnetic materials and superconducting circuits. This opens the door for the practical use of magnet-based quantum devices.
< Figure 2. Experimental Data. (a) Measurement results of magnon-magnon band anticrossing via continuous wave measurement, showing the formation of a strong coupling hybrid system. (b) Magnon pulse exchange oscillation phenomenon between YIG spheres upon single pulse application. It can be seen that magnon information is coherently transmitted at regular time intervals through the superconducting circuit. (c,d) Magnon interference phenomenon upon dual pulse application. The magnon information state can be arbitrarily controlled by adjusting the time interval and carrier frequency between pulses. >
Professor Kab-Jin Kim stated, “This project began with a bold, even unconventional idea proposed to the Global Singularity Research Program: ‘What if we could build a quantum computer with magnets?’ The journey has been fascinating, and this study not only opens a new field of quantum spintronics, but also marks a turning point in developing high-efficiency quantum information processing devices.”
The research was co-led by postdoctoral researcher Moojune Song (KAIST), Dr. Yi Li and Dr. Valentine Novosad from Argonne National Lab, and Prof. Axel Hoffmann’s team at UIUC. The results were published in Nature Communications on April 17 and npj Spintronics on April 1, 2025.
Paper 1: Single-shot magnon interference in a magnon-superconducting-resonator hybrid circuit, Nat. Commun. 16, 3649 (2025)
DOI: https://doi.org/10.1038/s41467-025-58482-2
Paper 2: Single-shot electrical detection of short-wavelength magnon pulse transmission in a magnonic ultra-thin-film waveguide, npj Spintronics 3, 12 (2025)
DOI: https://doi.org/10.1038/s44306-025-00072-5
The research was supported by KAIST’s Global Singularity Research Initiative, the National Research Foundation of Korea (including the Mid-Career Researcher, Leading Research Center, and Quantum Information Science Human Resource Development programs), and the U.S. Department of Energy.
2025.06.12 View 14171