Phys.org April 23, 2024 An international team of researchers (Japan, Australia) examined magnon spin currents in the ferrimagnetic garnet Tb3Fe5O12 with 4f electrons through the spin-Seebeck effect and neutron scattering measurements. The compound showed a magnetic compensation, where the spin-Seebeck signal reversed above and below K. Unpolarized neutron scattering unveiled two major magnon branches with finite energy gaps which were well explained in the framework of spin-wave theory. Their temperature dependencies and the direction of the precession motion of magnetic moments defined using polarized neutrons explained the reversal at and decay of the spin-Seebeck signals at low temperatures. According to […]
Tag Archives: Magnons
‘Shear sound waves’ provide the magic for linking ultrasound and magnetic waves
Phys.org March 29, 2024 An international team of researchers (Japan, Austria, Spain) observed strong coupling between magnons and surface acoustic wave (SAW) phonons in a thin CoFeB film constructed in an on-chip SAW resonator by analyzing SAW phonon dispersion ant crossings. They used a nanostructured SAW resonator design that allowed them to enhance shear-horizontal strain. This type of strain couples strongly to magnons. Their device design provided the tunability of the film thickness with a fixed phonon wavelength, which was a departure from the conventional approach in strong magnon-phonon coupling research. They detected a monotonic increase in the coupling strength […]
Research team takes neuromorphic computing a step forward
Phys.org July 24, 2023 Magnons undergo nonlinear multimode scattering processes at large input powers. In experiments and simulations, an international team of researchers (Germany, France) showed that the interaction between magnon modes of a confined magnetic vortex could be harnessed for pattern recognition. They studied the magnetic response to signals comprising sine wave pulses with frequencies corresponding to radial mode excitations. The amplitudes of three-magnon scattering results in the excitation of different azimuthal modes depended strongly on the input sequences. They showed that recognition rates as high as 99.4% could be attained for four-symbol sequences using the scattered modes, with […]
The next generation of information processing is through coherent gate operations
Phys.org July 14, 2021 Electromagnonics—the hybridization of spin excitations and electromagnetic waves—has been recognized as a promising candidate for coherent information processing in recent years. Among its various implementations, the lack of available approaches for real-time manipulation on the system dynamics has become a common and urgent limitation. A team of researchers in the US (Argonne National Laboratory, University of Chicago) introduced a fast and uniform modulation technique and demonstrated a series of benchmark coherent gate operations in hybrid magnonics, including semiclassical analogies of Landau-Zener transitions, Rabi oscillations, Ramsey interference, and controlled mode swap operations. Their approach lays the groundwork […]
First ever observation of ‘time crystals’ interacting
EurekAlert August 17, 2020 Protecting coherence is the main difficulty hindering the development of powerful quantum computers. An international team of researchers (Finland, UK, USA – Yale University, Russia) cooled superfluid helium-3 to within one ten thousandth of a degree from absolute zero and created two time crystals inside the superfluid. They observed an exchange of magnons between the time crystals leading to opposite-phase oscillations leading to opposite-phase oscillations in their populations while the defining periodic motion remains phase coherent throughout the experiment. The findings offer a basis to further investigate the fundamental properties of these phases, opening pathways for […]
Physicists find ways to overcome signal loss in magnonic circuits
Nanowerk January 2, 2020 Researchers in Russia analytically investigated properties of magnetostatic surface spin wave propagation in irregular narrow ferromagnetic waveguides that are important elements of magnonic logic. They demonstrated that the confinement effect in the narrow waveguide leads to multimode regime propagation, wave beats, and energy redistribution. These processes can be controlled by tuning the structure and excitation parameters. A gradual change in the waveguide width can be used to vary the spin wave energy density. Our results show that the impact of the width effect and the irregularity of the waveguide on the spin wave propagation are crucial. […]
Magnonic devices can replace electronics without much noise
Phys.org March 4, 2019 Researchers at UC Riverside created a chip that generated spin wave between transmitting and receiving antennae. They showed that the low-frequency noise of magnonic devices is dominated by the random telegraph signal noise rather than 1/f noise. It was also found that the noise level of surface magnons depends strongly on the power level, increasing sharply at the on-set of nonlinear dissipation. The presence of the random telegraph signal noise suggests that the current fluctuations involve random discrete macro events caused by an individual macro-scale fluctuator. The findings may help in developing the next generation of […]
Magnetic topological insulator makes its own magnetic field
Nanowerk November 19, 2018 In experiments, a team of researchers in the US (Rice University, Oak Ridge National Laboratory, NIST) found magnons in CrI3 samples. The structure of the magnon, and the movement of the magnetic wave was quite similar to how electron waves move around graphene. Both graphene and CrI3 contain Dirac points where electrons move just like photons, with zero effective mass, and if they move along the topological edges, there will be no resistance. This is important for dissipationless spintronic applications…read more. Open Access TECHNICAL ARTICLE
New devices could reduce excess heat in computers
Science Daily September 13, 2018 An international team of researchers (Germany, Norway, the Netherlands) demonstrated that antiferromagnetic iron oxide, which is the main component of rust, is a cheap and promising material to transport information with low excess heating at increased speeds. They used platinum wires on top of the insulating iron oxide to allow an electric current to pass close by. This electric current leads to a transfer of energy from the platinum into the iron oxide, thereby creating magnons. Antiferromagnets are unaffected by external magnetic fields, which is a key requirement for future data storage. Antiferromagnet-based devices can […]