Selective activation/deactivation of memristive interfaces in symmetrical devices

BENGIÓ, S; J. LECOURT; C. FERREYRA; ACHA, C; U. LUDERS; SÁNCHEZ, M J; AGUIRRE, M; D RUBI

Dresden

Conferencia; MEMRISYS 2019; 2019

Technische Universität Dresden

Resistive RRAM memories are firm candidates to constitute the next generation of non-volatilememories. RRAM memories operation is based on the so-called resistive switching effect, displayedby metal/oxide/metal systems able to reversible switch their electrical resistance between differentnon-volatile states. Resistive switching has been ubiquitously found in transition metal oxides, bothbinary (TaOx, TiOx, HfOx) and complex (cuprates, manganites). In many cases, the resistivechanges are mainly localized at oxide/metal interfaces where, for example, oxygen vacancieselectro-migration modulates Schottky barriers. Common wisdom says that in order to maximize thewindow between high and low resistance states -one of the fundamental figures that characterize thememory behavior- one must work with asymmetric devices, where one of the interfaces is activeand concentrates the resistive changes, while the other one remains ohmic and inactive. Suchasymmetry is usually achieved by using different metals for both electrodes. In this work we showthat by appropriately tuning the electrical stimulus protocol in symmetrical Ag/La1/3Ca2/3MnO3/Agand Pt/TaOx/Pt devices, it is possible to selectively activate or deactivate the resistive switchingresponse of each interface, obtaining electrical responses similar to those found in asymmetricdevices. By the adaptation of the VEOV model to both systems [1,2], we numerically reproduce theexperimental measurements and get a deep insight into the involved oxygen vacancies dynamics.