Antiferromagnetic magnons possess high speed and are immune to external disturbance, making them promising for future magnonic circuits. In this Letter, we report the observation of gapless magnons in an easy-axis antiferromagnet α-Fe_{2}O_{3} at low temperatures. These antiferromagnetic magnons are detected at nearly zero frequency by all-electrical spin-wave spectroscopy and propagate along antiferromagnetic domain walls as revealed by our theoretical model and simulations. Moreover, we demonstrate high coherency of these gapless magnons by showing their strong coupling with microwave photons. Our results open the pathway for antiferromagnetic texture based magnonic devices operating at microwave frequencies.
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http://dx.doi.org/10.1103/PhysRevLett.134.056701 | DOI Listing |
Phys Rev Lett
February 2025
International Quantum Academy, Shenzhen 518048, China.
Antiferromagnetic magnons possess high speed and are immune to external disturbance, making them promising for future magnonic circuits. In this Letter, we report the observation of gapless magnons in an easy-axis antiferromagnet α-Fe_{2}O_{3} at low temperatures. These antiferromagnetic magnons are detected at nearly zero frequency by all-electrical spin-wave spectroscopy and propagate along antiferromagnetic domain walls as revealed by our theoretical model and simulations.
View Article and Find Full Text PDFPhys Rev Lett
October 2024
University of Chinese Academy of Sciences, Kavli Institute for Theoretical Sciences, Beijing 100190, China.
We investigate thermomagnetic transport in an ultracold atomic system with two ferromagnets linked via a magnetic quantum point contact. Using the nonequilibrium Green's function approach, we show a divergence in spin conductance and a slowing down of spin relaxation that manifest in the weak effective-Zeeman-field limit. These anomalous spin dynamics result from the magnonic critical point at which magnons become gapless due to spontaneous magnetization.
View Article and Find Full Text PDFRep Prog Phys
October 2024
Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan 430071, People's Republic of China.
We present analytical results of the fundamental properties of the one-dimensional (1D) Hubbard model with a repulsive interaction. The new model results with arbitrary external fields include: (I) using the exact solutions of the Bethe ansatz equations of the Hubbard model, we first rigorously calculate the gapless spin and charge excitations, exhibiting exotic features of fractionalized spinons and holons. We then investigate the gapped excitations in terms of the spin string and thek-Λstring bound states at arbitrary driving fields, showing subtle differences in spin magnons and charge-pair excitations.
View Article and Find Full Text PDFACS Appl Mater Interfaces
November 2023
Department of Physics, University of South Florida, Tampa, Florida 33620, United States.
Recently, Heusler alloy-based spin gapless semiconductors (SGSs) with high Curie temperature () and sizable spin polarization have emerged as potential candidates for tunable spintronic applications. We report comprehensive investigation of the temperature-dependent ANE and intrinsic longitudinal spin Seebeck effect (LSSE) in CoFeCrGa thin films grown on MgO substrates. Our findings show that the anomalous Nernst coefficient for the MgO/CoFeCrGa (95 nm) film is ≈1.
View Article and Find Full Text PDFJ Phys Condens Matter
July 2021
Department of Physics, Renmin University of China, Beijing 100872, People's Republic of China.
We find that the Schwinger boson mean field theory (SBMFT) supplemented with Gutzwiller projection provides an exceedingly accurate description for the ground state of the spin-12triangular lattice antiferromagnetic Heisenberg model (spin-12TLHAF). However, we find the SBMFT fails even qualitatively in the description of the dynamical behavior of the system. In particular, the SBMFT fails to predict the Goldstone mode in the magnetic ordered phase.
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