講演情報
[25a-P01-27]Theoretical Analysis of Magnetic Damping by Four-Magnon Interactions for NiO from Tensor Representation of Second Quantization
〇(D)Andi Gumarilang Ahmadi1, Kenji Nawa1,2, Kohji Nakamura1 (1.Mie Univ., 2.NIMS)
キーワード：
Magnetic Damping、Four Magnon Interactions、NiO
Antiferromagnetic insulator NiO exhibits ultra-low magnetic Gilbert damping due to the weak spin-orbit coupling, which thus leads to a small energy dissipation for two non-degenerate magnon modes, labeled as α and β-modes. In this presentation, we investigate the magnetic damping properties induced by the four-magnon scattering, in which a fourth-rank tensor representation of second quantization field operators is employed. First, we calculated the magnetic damping constants for two magnon modes confirming broadband THz spectroscopy results. Secondly, when T increases at q=0, the contributions of intra- and inter-mode interactions to the magnetic damping constant increases. Thirdly, fixing T = 300 K and varying from q to T in the Brillouin zone, we found that the intra-mode interaction in the α-mode magnon exhibits a minimum value of magnetic damping constant at q≅0.04[Γ-T], while in the β-mode, both the intra- and inter-mode interactions exhibit minimum magnetic damping constants at q≅0.02[Γ-T] and 0.12[Γ-T] respectively.