Coherently controlled spin precession in canted antiferromagnetic YFeO3using terahertz magnetic field

We investigate the details of the precessional motion of the magnetic moment in canted antiferromagnetic YFeO3, which is excited by a linearly polarized terahertz (THz) pulse at room temperature. By tuning the spectral component of the input THz pulse around the quasi-ferromagnetic mode located near 0.3 THz, we have experimentally clarified the resonance effect in the THz control of the spin state. We were able to confirm this result from the simulation based on the Landau–Lifshitz–Gilbert equation with the two sub-lattice model for the canted antiferromagnet. Finally, we discuss a crossover from a linear to a nonlinear magnetic response to the input THz pulse during the THz-induced precessional switching of the magnetization.