The Osaka Metropolitan University is located in Osaka.

wireless energy
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6G will be a reality in the near future. Magnetic materials are needed for the development of wireless communication systems. Scientists from Osaka Metropolitan University have detected an unprecedented collective resonance at high frequencies in a magnetic superstructure called a chiral spin soliton lattice. The study was published in a peer reviewed journal.

The current few gigahertz band needs to be expanded to over 100 GHz in the future. Existing magnetic materials used in communication equipment can only absorb microwaves up to 70 GHz with a practical-strength magnetic field. The research team led by Professor Togawa from Osaka Metropolitan University looked into the helicoidal spin superstructure CSL.

The external magnetic field strength can be changed by changing the structure of CLS. Frequency ranges for conventional ferromagnetic materials are larger than those for the CSL phonon mode. It has never been observed in experiments.

The team tried to find a way to use the CSL phonon mode. They first observed the resonance behavior of CSL when it was first generated. Magnetic resonance signals can be detected using a microwave circuit.

The researchers observed resonance in three different modes. In the Kittel mode, resonance frequencies increase only if the magnetic field strength increases, meaning that creating the high frequencies needed for 6G would be impractical. The asymmetric mode didn't find the CSL phonon.

In the multiple resonance mode, the CSL phonon was detected, in contrast to what is observed with magnetic materials currently in use. It is possible that this phenomenon will allow a boost to over 100 GHz with a weak magnetic field.

The resonance motion was observed for the first time by the authors. The resonance can be controlled over a wide band up to the sub-terahertz band. This wideband and variable Frequency characteristic is expected to be used in research and development of next- generation communication technologies.

More information: Y. Shimamoto et al, Observation of Collective Resonance Modes in a Chiral Spin Soliton Lattice with Tunable Magnon Dispersion, Physical Review Letters (2022). DOI: 10.1103/PhysRevLett.128.247203 Journal information: Physical Review Letters Provided by Osaka Metropolitan University