Influence of Li Ions on Memristor Properties of Capacitor Structures Based on Nanocomposites (Co40Fe40B20)x(LiNbO3)100–x

Abstract

The paper reveals the influence of Li, B and the composition of metal contacts on the processes of resistive switching in memristive structures M/NC/D/M. After field exposure in structures Cu/(Co₅₀Fe₅₀)_x(LiNbO₃)_100–x/s-LiNbO₃/Cu/sitall, Cu/(Co₅₀Fe₅₀)_x(LiNbO₃)_100–x/d-LiNbO₃/Cu/sitall and Cu/(Co₄₀Fe₄₀B₂₀)_x(SiO₂)_100–x/d LiNbO₃/Cu/sitall at x < 13 was detected a residual voltage (up to 16 mV) due to the electromigration of Li ions, that leading to a “reversible” type of VAC hysteresis and instability of the time dependencies of induced resistive states. In the structures of Cu/(Co₄₀Fe₄₀B₂₀)_x(LiNbO₃)_100–x/s-LiNbO₃/Cu/sitall, Cr/Cu/Cr/(Co₄₀Fe₄₀B₂₀)_x(LiNbO₃)_100–x/s-LiNbO₃/Cr/Cu/Cr/sitall containing B, the residual voltage is reduced by formation of chemical compounds B with percolated Li atoms. When limiting the electromigration of Li ions, the main mechanism of resistive switching is the processes of electromigration of oxygen vacancies in the dielectric oxide layer. Suppression of residual voltage in the Cr/Cu/Cr/(Co₅₀Fe₅₀)_x(LiNbO₃)_100–x/s-LiNbO₃/Cr/Cu/Cr/sitall structure due to the introduction of a Cr buffer layer that does not dissolve Li leads to the absence of bipolar resistive switching in these structures.