Magnetization states of canted antiferromagnetic YFeO3 investigated by terahertz time-domain spectroscopy

We investigate magnetization states of a canted antiferromagnetic YFeO3 by using terahertz (THz) time-domain spectroscopy under a variation of an external magnetic field. As a quasi-ferromagnetic mode near 0.3 THz is excited by the magnetic field of the THz pulse, a precession of the magnetic moment and its induction decay radiate the THz wave. Since oppositely aligned magnetic domains emit the circularly/elliptically polarized THz waves with opposite helicities, a detection of specific polarization of the THz wave shows a clear hysteresis behavior in good agreement with a magnetization curve obtained as a function of the applied magnetic field. Furthermore, time-domain measurement of excited magnetic moment can provide direct information about the magnetization decay dynamics. (C) 2015 AIP Publishing LLC.