Fig. 1. Position of THz waves in the frequency spectrum

Fig. 2. (a) Illustration showing the dynamics of magnetic moment. The magnetic moment is tilted within y-z plane by the impulsive magnetic field along x axis (blue arrow), and begins precession motion around z axis; (b) Ordering of Fe³⁺ magnetic moments in YFeO₃^[12]

Fig. 3. (a) Magnetization temperature dependence of Sm_0.4Er_0.6FeO₃ single crystal in the applied field H=100 Oe along the a-axis and c-axis^[26]; (b) Temperature dependence of resonance amplitude and frequency^[26]

Fig. 4. Spin control of TmFeO₃ by a terahertz-induced anisotropy torque ^[31]. (a) The ground state of Tm^3＋;(b) Ultrafast transitions between energy levels of Tm^3＋ induced by terahertz pulses

Fig. 5. Antenna-enhanced THz spin dynamics ^[32]. (a) Schematic of the gold bowtie antenna on TmFeO₃; (b) Real incident THz waveform; (c) Experimentally detected polarization rotation signal as a function of the delay time t