Trade-off between number of conductance states and variability of conductance change in Pr0.7Ca0.3MnO3-based synapse device

The characteristics of Pr0.7Ca0.3MnO3 (PCMO)-based resistive change memory were evaluated as a synapse device for a emerging computing system inspired by a biological brain. The evaluated samples structured with various reactive top electrodes exhibited a dependence on the metal-oxide free energy. More conductance states which can improve the performance of the brain-inspired computing system were achieved in a sample having a low metal-oxide free energy. During the increase and decrease in the conductance, the low metal-oxide free energy also resulted in an asymmetric conductance change leading to degradation in the computational accuracy of the brain-inspired computing system. The results demonstrated a trade-off between the number of conductance states and the variation in the conductance change in the PCMO-based synapse device.