Resistive switching duality: insulator-to-metal vs. metal-to-insulator switching*

Electrical triggering of metal-insulator transitions offers an opportunity to build energy-efficient and scalable electronics. While insulator-to-metal (I-M) switching in materials such as VO₂ is thoroughly studied, much less is known about an opposite metal-to-insulator (M-I) switching. We present a detailed study of M-I switching in (La,Sr)MnO₃ (LSMO). Negative differential resistance (NDR) region in the I-V characteristic is necessary for the resistive switching. By comparing LSMO to VO₂, we observe an interesting duality: the N-type NDR in LSMO is a “mirror reflection” of the S-type NDR in VO₂. Using Kerr effect imaging, we found that an insulating blocking domain perpendicular to the current flow forms in the LSMO during the NDR. This behavior is reciprocal to VO₂ in which a conducting filament parallel to the current flow emerges during the NDR. M-I and I-M resistive switchings complement each other providing a broad range of nonlinear electrical properties, which could allow designing of complex electronic devices.