Enhanced remnant polarization in ferroelectric Bi6Fe2Ti3O18 thin films

For practical applications of ferroelectric memory, a large remnant polarization in nontoxic Pb-free ferroelectric materials is required.

PZT FILM GENERATOR DRIVEN BY ULTRASONIC WAVE

Energy harvesting was demonstrated in hydrothermal PZT nanocrystal films driven by ultrasound. With high temperature sintering and solution infiltration, PZT films with nanograin size was found to exhibit bulk-like properties such as large remnant polarization of 42 μC/cm2. With the bulk-like properties, a packaged PZT film device was demonstrated to be capable of converting mechanical energy carried by the ultrasonic wave into electrical energy in a reliable and efficient way. The result suggests an alternative potential solution for energy harvesting application.

Epitaxial Ferroelectric Heterostructures of Isotropic Metallc Oxide (SrRuO3) and Pb(Zr0.52Ti0.48)O3

We have fabricated epitaxial ferroelectric heterostructures of isotropic metallic oxide (SrRuO3) and ferroelectric thin films [SrRuO3/Pb(Zr0.52Ti0.48)O3 /SrRuO3] on (100) SrTiO3 and YSZ buffer layered Si substrates by 90° off-axis sputtering. These heterostructures have high crystalline quality and coherent interfaces as revealed by X-ray diffraction, Rutherford backscattering spectroscopy and cross-sectional transmission electron microscopy. The ferroelectric layers exhibit superior fatigue characteristics over 1010 cycles with large remnant polarization.

Ferroelectric La-Sr-Co-O / Pb-Zr-TI-O / La-Sr-Co-O Heterostructures on Silicon: Reliability Testing

We report results of pulsed electrical testing of ferroelectric Pb0.9La0.1Zr0.2Ti0.8O3 thin film capacitors with symmetrical La-Sr-Co-O top and bottom electrodes at room temperature and at 100°C. They have been grown on [001] Si with a Yttria stabilized zirconia (YSZ) buffer layer. A layered perovskite “template” layer (200-300Å thick), grown between the YSZ buffer layer and the bottom La-Sr-Co-O electrode, is critical for obtaining the required orientation of the subsequent layers. When compared to the capacitors grown with Y-Ba-Cu-O (YBCO) top and bottom electrodes, these structures possess two advantages : (1) the growth temperatures are lower by 60-150°C; (ii) the capacitors show a large remnant polarization, δP, ( δP = switched polarization -non-switched polarization), 25-30 μC/cm2, for an applied voltage of only 2V (applied field of 70kV/cm). The fatigue, retention and aging characteristics of these new structures are excellent at both room temperature and at 100°C.