Functional signal transformer based on a composite multiferroic

Nonlinear transfer functions of a voltage converter realized in a straintronic composite magnetic-piezoelectric structure within the area of spin reorientation (SR) are studied numerically and analytically. It is shown that at the SR critical point the transfer function has the shape of an inverse sigmoid. As the magnetizing field strength decreases, the function transforms into a reversible hysteresis loop. Under a pulsed impact, the threshold effect of generation of an opposite-polarity spike is displayed, which is followed by the system return to its initial state. When the input represents a sequence of short pulses critical with respect to the time of impact, the system switches between bistable spin states with inversion of the output voltage polarity. The qualitatively different functions of nonlinear voltage transform can be performed in one and the same structure by controlling the magnetic field strength and input signals' parameters.