Electric Pulse Induced Resistive Switching in silver manganite contacts

NÉSTOR GHENZI; FERNANDO GOMEZ MARLASCA; PABLO LEVY

Congreso; SOLIDOS 09; 2009

Non volatile memory concepts for electronic applications are presently based on resistance change rather than in charge storage. Electric pulse induced resistance switching(RS) was shown to produce useful retentiontime capability for massive applications.Several basic and applied research teams arepresently devoted to the study of transitionmetal oxides contacted through metal electrodesdriven by appealing fast switching andscalability.Manganites exhibit bipolar type RS inwhich electrochemical migration of oxygenions and vacancies is regarded as the drivingmechanism. RS takes place at the interfacebetween the metal electrode and the oxide, inan interface - type path, as described thoroughlyby A.Sawa [1] and references therein.Electric field at the interface produces oxygenions to be detrapped, disrupting Mn - O -Mn double exchange conducting chains. Evidencefor an oxygen diffusion mechanism bymeans of electric transport measurements [2]was recently obtained by means of a HysteresisSwitching Loop (HSL) procedure inwhich pulses of varying amplitude determinethe state of the interface, and a small bias isused to test the remnant state. [2, 3] Here weapply a similar procedure to show that theactual electric field acting at the oxygen vacancieslocated at the interface determinesthe remnant resistance level at each pulsedelectrode. This fact is further shown to allowobtaining RS at reduced stimulus, dependingon the previous state of the interface.We performed a systematic study on amultiterminal silver - manganite sample atroom temperature, with millimeter sized handpainted electrodes. Resistive switching at asilver manganite interface is studied bymeans of instantaneous and remnant responseto bipolar current pulses. Complementarybehaviour at pulsed electrodes is found inboth cases above the threshold for switching.A loop protocol is used to determine the stateof the interface either in high or low resistancestates. By performing minor loops atselected states, the threshold for switching isfound to be determined by the density of vacanciesat the interface. Switching at reducedcurrent density stimulus is obtained bychoosing the appropriate initial state, whichin turn determines the actual electric fieldand the remnant resistance value. We discussthe transport mechanism in terms of oxygenvacancy detrapping.We acknowledge A.G.Leyva for samplepreparation, and discussions with M. Rozenberg,M.J.Sánchez, C.Acha and R.Weht. Researchpartially supported by MeMO(PIP2008)References[1] A. Sawa, Materials Today, 11, 28 (2008).[2] Y.B. Nian, J. Strozier, N. Wu, X. Chen andA. Ignatiev, Phys. Rev.Lett. 98, 146403 (2007).[3] F Gomez-Marlasca and P Levy, J. Phys.:Conf. Ser. 167, 012036 (2009).