analog switching is studied at intermediate resistive states and as a function of dc cycling. A
universal 1/f α-type behavior is found, with a frequency exponent of α≈ 1.2 that is
independent of the applied reset voltage or the device resistance and is attributed to the
intrinsic abundance of oxygen vacancies unique to the structure of yttria. Remarkably, the
noise magnitude in the high resistive state systematically decreases through dc training …