Frugal discrete memristive device based on potassium permanganate solution

Many thin film-based devices with solid electrolytes have been studied for memristive applications. Herein, we report a simple and facile way to fabricate solution-based, low-cost, and discrete two-terminal memristive devices using the KMnO4 solution. The water and methanol were used as a solvent to prepare different concentrations of KMnO4 to carry out the optimization study. Furthermore, the effect of KMnO4 concentration with aqueous and methanol solvents was studied with the help of current-voltage, device charge, charge-flux, and cyclic endurance properties. Interestingly, all developed devices show the asymmetric time-domain charge and double valued charge-flux properties, suggesting that aqueous KMnO4 and methanol-KMnO4 based devices are non-ideal memristors or memristive devices. The statistical measures such as cumulative probability and coefficient of variation are reported for the memristive devices. The possible switching mechanism of the discrete memristive was tried to explain with the UV-visible spectrum and theoretical framework. The optimized device was further studied using the cyclic voltammogram, Bode plot, and Nyquist plot. An equivalent circuit was derived for the optimized discrete memristive device using electrochemical impendence spectroscopy results. The results of the present investigation are beneficial to develop programmable analog circuits, volatile memory, and synaptic devices using discrete memristive devices

Capacitive coupled non-zero I-V and type-II memristive properties of the NiFe2O4-TiO2 nanocomposite

In the present work, we have demonstrated the capacitive coupled non-zero and type-II hysteresis behavior of nickel ferrite (NFO)-titanium oxide (TiO2) nanocomposite. For this, NFO nanoparticles (NPs) and TiO2 NPs were synthesized using hydrothermal and sol-gel method, respectively. The NFO-TiO2 nanocomposite was prepared using a solid-state reaction method and characterized by X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscope, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy. The electrical results of the NFO-TiO2 memory device have shown non-zero I-V (unable to cross at origin), cross-over I-V and type-II hysteresis (tangential hysteresis loops) properties and their occurrence was depended upon the magnitude of the electrical stimulus. To further clarify the dominance of the memristive and type-II properties, we have calculated the charge-flux and non-transversal di/dv(t) characteristics of the device based on experimental results. The charge transport mechanisms were investigated and a plausible resistive switching mechanism was reported. Our investigations provide some insights to explain the non-zero and type-II hysteresis behavior of the memristive devices

Review of Electrochemically Synthesized Resistive Switching Devices: Memory Storage, Neuromorphic Computing, and Sensing Applications

Resistive-switching-based memory devices meet most of the requirements for use in next-generation information and communication technology applications, including standalone memory devices, neuromorphic hardware, and embedded sensing devices with on-chip storage, due to their low cost, excellent memory retention, compatibility with 3D integration, in-memory computing capabilities, and ease of fabrication. Electrochemical synthesis is the most widespread technique for the fabrication of state-of-the-art memory devices. The present review article summarizes the electrochemical approaches that have been proposed for the fabrication of switching, memristor, and memristive devices for memory storage, neuromorphic computing, and sensing applications, highlighting their various advantages and performance metrics. We also present the challenges and future research directions for this field in the concluding section