講演情報
[22a-P01-34]Unveiling Antiferromagnetic Magnon Resonance Frequencies of 3d Transition-Metal Monoxides via Landau-Lifshitz Equation
〇(D)Andi Gumarilang Ahmadi1, Kenji Nawa1,2, Koji Nakamura1 (1.Mie Univ., 2.NIMS)
キーワード：
Antiferromagnetic Resonance Frequency、3d Transition-Metal Monoxides、Magnon
Recent progresses in wireless communication have incited researchers to pursue novel materials capable of propagating THz waves. Antiferromagnetic insulator 3d transition-metal (TM) monoxides (MnO, FeO, CoO, and NiO) can propagate a collective magnetic excitation, called magnon, in antiferromagnetic resonance (AFMR) frequencies ranges from 10$^{-1}$ to 10 THz. However, magnetic properties, such as magnetic anisotropy, magnetic easy-axis, and spin-exchange constant, on these materials vary and affect AFMR frequency and magnetic structures stability. Here, we investigated the effect of magnetic parameters variation on the AFMR in these materials by developing a contour plot of AFMR frequency based on Landau-Lifshitz model and taking account magnetic dipole-dipole interaction, single-ion anisotropy, and Heisenberg interaction. In this presentation, we will demonstrate that for magnetic easy-axis in $[\bar{1}\bar{1}2]$ direction, magnon frequency will have zero imaginary part, whereas for magnetic easy-axis in $[111]$ direction, magnon frequency will have non-zero imaginary part, indicating unstable magnetic structures. We also confirm the AFMR frequency of NiO and MnO, while that of CoO is underestimated, indicating other magnetic interaction might exist. Finally, we present the effect of several magnetic parameters on magnon dispersion of 3d TM monoxides.