Self-assembled nanoscale capacitor cells based on ultrathin BiFeO₃films

Ultrathin multiferroic BiFeO3(BFO) films with self-assembled surface nano-islands on La0.67Sr0.33MnO3/(100) SrTiO3substrates are fabricated by a one-step pulsed laser deposition process using the Bi-rich BFO target. It is revealed that these surface nano-islands mainly consist of conductive Bi2O3outgrowths, which serve as top electrodes for the nanoscale BFO capacitor cells with lateral size of 10-30nm. The ferroelectric BFO layer underneath these Bi2O3nanoislands prefers certain complex domain structure with vertical and antiparallel polarization components (the so-called "anti-domain structure") and reduced domain switching fields. Moreover, these nanoscale capacitor cells exhibit the resistive switching IV behavior, offering opportunities for application in ultrahigh density non-volatile memories.