1,720,965 research outputs found
Origin of stochastic resistive switching in devices with phenomenologically identical initial states
No full textNanoscale resistive switching devices are nowadays widely employed in applications of storage, logic and computing. The switching mechanism of metal oxide based devices is normally assumed to be the filamentary formation and rupture within the devices’ active cores but the origin of filaments growth is still controversial. Previous research has already demonstrated that initial filamentary states could significantly affect the devices’ switching dynamics and final resistance distributions. Here we demonstrate the relation between pristine resistive states and distribution of filaments via modeling the switching dynamics by utilizing a current percolation circuit. We show that devices with identical initial resistive states could attain distinct plausible filamentary distributions and correspondingly manifest very dissimilar switching dynamics even when biased with similar stimuli
Pulse-induced resistive and capacitive switching in TiO<sub>2</sub> ReRAM
No full textIn this study, we provide the experimental evidence of the coexistence of resistive and capacitive features in nanoscale TiO2 based solid state Resistive Random Access Memory (ReRAM). Biasing the devices with voltage sweeps exhibits non-zero crossing I-V characteristics, serving as a signature of capacitive effects. Here, we show that both resistive and capacitive states can be concurrently set via voltage pulsing
Memory Impedance in TiO2 based Metal-Insulator-Metal Devices
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Resistive switching characteristics of indium–tin-oxide thin film devices
No full textWe demonstrate that indium–tin-oxide (ITO), when used as an active core material in metal–insulator–metal type devices, facilitates resistive switching. We fabricated devices both on silicon as well as quartz wafers, to demonstrate transparent devices. Furthermore, we investigated the influence of active core thickness on the devices’ characteristics, showing that their switching threshold scales with the ITO thickness. Unipolar switching was observed for devices comprising thick ITO films while bipolar switching occurred for both thin and thick ITO films at the absence of high voltage forming steps. Our study demonstrates that ITO holds good potential for resistive memory applications
Memristive devices as parameter setting elements in programmable gain amplifiers
No full textIn this paper, we investigate the AC performance of a variable gain amplifier that utilizes an in-house manufactured memristor as a gain setting element. Analysis includes frequency and phase responses as the memristor is programmed at different resistive states. A TiO2-based solid-state memristor was employed in the feedback branch of an inverting voltage amplifier and was programmed externally. We have also observed indications of memcapacitive effects and a correlation with resistive states is presented. We demonstrate that our TiO2 memristive devices, although possessing relatively low ROFF/RON switching ratios (~10), are versatile and can be used reliably in programmable gain amplifiers.&more..
Pulse-induced resistive and capacitive switching in TiO2 thin film devices
Full text linkIn this study we exploit the non-zero crossing current-voltage characteristics exhibited by nanoscale TiO2 based solid-state memristors. We demonstrate that the effective resistance and capacitance of such two terminal devices can be modulated simultaneously by appropriate voltage pulsing. Our results prove that both resistive and capacitive switching arise naturally in nanoscale Pt/TiO2/Pt devices under an external bias, this behaviour being governed by the formation/disruption of conductive filaments through the TiO2 thin film
Coexistence of memory-resistance and memory-capacitance in TiO2 solid state devices
Full text linkThis work exploits the coexistence of both resistance and capacitance memory effects in TiO2 based two terminal cells. Our Pt/TiO2/TiOx/Pt devices exhibit an interesting combination of hysteresis and non-zero crossing in their current-voltage (I-V) characteristic that indicate the presence of capacitive states. Our experimental results demonstrate that both resistance and capacitance states can be simultaneously set via either voltage cycling and/or voltage pulses. We argue that these states modulations occur due to bias induced reduction of the TiOx active layer via the displacement of ionic species
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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