As theoretically
predicted by Prof. Chua, the input signal frequency has a major impact on the
electrical behavior of memristors. According with one of the so-called fingerprints
of such devices, the resistive window, <i>i.e.</i> the difference between the
low and high resistance states, shrinks as the frequency increases for a given
input signal amplitude. Physically, this effect stems from the incapability of
ions/vacancies to follow the external electrical stimulus. In terms of the electrical
behavior, the collapse of the resistive window can be ascribed to the shift of
the set/reset voltages toward higher values. Moreover, for a given frequency,
the resistance window increases with the signal amplitude. In this letter, we
show that both phenomena are the two sides of the same coin and that can be
consistently explained after considering the snapback effect and a balance
model equation for the device memory state.