B. Allouche

Resistive Switching Hysteresis in Thin Films of Bismuth Ferrite

We have studied the resistive switching (RS) phenomenon in series of BiFeO3 thin films of thickness of 40 – 154 nm deposited by PLD technique on conducting Nb-doped substrate of SrTiO3 and with Pt top electrodes. It was found that 154 nm film demonstrates the interface-provided I–V characteristic of Schottky diode when the applied voltage does not exceed the threshold value Vd = 1.3 V. The RS phenomenon appears as the current hysteresis loop during the 0 → Vm → 0 → −Vm → 0 voltage sweep cycle, provided that the maximal stop-voltage Vm is larger than Vd. For thinner films neither diode-like I–V behavior nor substantial RS effect were observed. The results are interpreted in terms of the filamentary model of the mobile oxygen vacancies.

Oxygen-deficient GdK2Nb5O15 ferroelectric epitaxial thin film

The ferroelectric compound GdK2Nb5O15 (GKN) thin film with tetragonal-tungsten-bronze–type structure was grown by pulsed-laser deposition on (001)SrRuO3/La0.5Sr0.5CoO3/MgO substrate. Using X-ray diffraction analysis we demonstrate that the phase transition temperature in the GKN thin film was shifted to high temperatures due to substrate-induced stress. Impedance spectroscopy investigations show Maxwell-Wagner–type conduction at low frequencies, which leads to resistive switching. Oxygen vacancies and temperature effects were studied to highlight the stability of the resistive switching behavior in the GKN thin film.