Electric field-controlled crossover effect in oxygen-deficient titanium-oxide memory bits

In this letter, we report an unusual crossover in the current-voltage characteristics of forming-free titanium oxide-based memory bits. The voltage at which crossover between high and low resistance states take place, V-cr gradually shifts to lower bias values with either decreasing sweeping rates, increasing maximum scan voltage or increasing current compliance. Interestingly, the crossover effect is not pronounced for reduced-oxide based memory bits. The mechanism behind these changes in the I-V curves is discussed.