Active Magnetoelectric Control of Terahertz Spin Current

Abstract: Electrical control of photogenerated THz spin current pulses from a spintronic emitter has been at the forefront for the development of scalable, cost-efficient, wideband opto-spintronics devices. Artificially combined ferroelectric and ferromagnet heterostructure provides the potential avenue to control the spin dynamics efficiently utilizing the magnetoelectric coupling. The demonstration of the electric field control of spin dynamics has so far been limited up to gigahertz frequencies. Here, we demonstrate the electric field mediated piezoelectric strain control of photogenerated THz spin current pulse from a multiferroic spintronic emitter. The phase reversal of the THz spin current pulse is obtained from the combined effect of piezoelectric strain and a small constant magnetic field applied opposite to the initial magnetization of the ferromagnet. The piezoelectric strain-controlled phase switching of THz spin current thus opens a door to develop efficient strain engineered scalable on-chip THz spintronics devices.