Studies on the resistance switching properties of the La0.5Ca0.5MnO3/Nb : SrTiO3 heterojunction

In this study, we have investigated the resistance switching behavior of the La0.5Ca0.5MnO3/Nb:SrTiO3 heterojunction. The junction shows a negative resistance switching ratio (ER) below 140 K. When 220 K > T ≥ 140 K , the ER goes from negative to positive with increasing bias voltage. When T > 220 K, the junction shows a positive ER. This variation from a negative to a positive value indicates that the ER is determined primarily by two phenomena: (a) the negative ER value can be attributed to a disruption of the charge-ordered insulating domains in La0.5Ca0.5MnO3 under large electric fields, and (b) the positive ER value at high temperatures is due to the modulation of the interface barrier width driven by the electrochemical migration of oxygen vacancies.