Fig. 5
The memory retention for synaptic weight of Pt/HfOx/ZnOx/TiN memristive device: transformation from STP to LTP induced by repetitive pulse stimulation. a–e Memory forgetting process (black solid circle in figure) was experienced by different numbers of pulse stimulation, in which the normalized data was fitted using Eq. 1. f The relaxation time (τ) changes with the number of pulses by fitting the data from Fig. 5(a–e)