Magnons are tiny particles that represent collective spin-wave excitations in materials with magnetic order. Understanding how these collective modes interact is essential for grasping significant many-body effects in such systems. Moreover, it’s crucial for developing devices that can transport and process information at high speeds using magnons. However, figuring out how individual magnon modes interact with each other has been a persistent challenge in the field.
A recent study has made a promising discovery in developing magnonic computers. Researchers experimented with creating different kinds of ripples in the magnetic field of a thin metal plate. They found that these ripples, called magnons, interacted with each other in a nonlinear way. This means that the output was not directly proportional to the input, which is crucial for computing applications.
Most previous research in this area focused on studying one type of magnon at a time under stable conditions called equilibrium. But in this study, the researchers pushed the system out of equilibrium by manipulating the magnons.
This research is part of a larger collaboration between scientists and engineers from UCLA, MIT, the University of Texas at Austin, and the University of Tokyo in Japan. Supported by government and private grants, this collaboration aims to advance our understanding of nonequilibrium physics.
One crucial technology used in this study is terahertz lasers, which can add energy to samples and measure their properties. This technology, already employed in chemistry and medical imaging, has the potential to revolutionize our understanding of magnetic fields.
The researchers applied laser pulses to a thin metal plate made of a special alloy containing yttrium. By carefully controlling the magnetic field and laser pulses, they could create and measure interactions between different types of magnons.
This discovery could have critical applications in signal processing and information manipulation using magnetism. It also highlights the importance of training the next generation of scientists and engineers to tackle complex challenges in physics and engineering.
Co-author Jonathan Curtis, a UCLA postdoctoral researcher in the NarangLab, said, “Clearly demonstrating this nonlinear interaction would be important for any sort of application based on signal processing. Mixing signals like this could allow us to convert between different magnetic inputs and outputs, which is what you need for a device that relies on manipulating information magnetically.”
Prineha Narang, a co-author of the study and professor of physical sciences at UCLA College, said, “Trainees are vital to the current study, as well as the larger project.”
“This is a really hard, multiyear endeavor with a lot of pieces. What’s the right system, and how do we go about working with it? How do we think about making predictions? How do we limit the system so it’s behaving as we want it to? We wouldn’t be able to do this without talented students and postdocs.”
Journal Reference:
- Zhang, Z., Gao, F.Y., Curtis, J.B. et al. Terahertz field-induced nonlinear coupling of two magnon modes in an antiferromagnet. Nat. Phys. (2024). DOI: 10.1038/s41567-024-02386-3