Review of resistance switching of ferroelectrics and oxides in quest for unconventional electronic mechanisms

Resistance switching effects in perovskite oxides, which acquire recently intense interests for the application to the resistance-random-access memories, are reviewed with emphasis on paraelectric and ferroelectric oxides. We examine whether the switching mechanism is the electric field effect or the current injection effect as well as the in nanometer scale writing/reading/erasing. Based on these examinations, we search for the traces of unconventional electronic switching, as opposed to thermal and defect mechanisms that are considered responsible for the most results in the past.