SrBi 4 Ti 4 O 15 thin films and their ferroelectric fatigue behaviors under varying switching pulse widths and frequencies

Polycrystalline ferroelectric SrBi4Ti4O15 thin films were prepared on Pt-coated silicon substrates by pulsed laser deposition. Structures of the films were analyzed by x-ray diffraction, atomic force microscopy (AFM) and scanning electron microscopy. At an applied field of 275 kV/cm, the films showed good hysteresis loops with remnant polarization (Pr), saturated polarization (Ps) and coercive field (Ec) of 3.11 μC/cm2, 7.81 μC/cm2 and 68 kV/cm, respectively. At 120 kV/cm switching pulse field, fatigue tests were carried out systematically by varying the switching pulsewidth with a fixed duty cycle and with a fixed switching period, respectively. A gradual increase followed by an abrupt increase of the fatigue rate was observed with the increase of the switching pulsewidth. Field-induced defect diffusion was used to explain the results.