Neodymium-doped Bi4Ti3O12 (BNT) films are evaluated for use as lead-free thin-film piezoelectrics in microelectromechanical systems. Bi4Ti3O12, Bi3.25La0.75Ti3O12, and Bi3.25Nd0.75Ti3O12 films were fabricated by chemical solution deposition on Pt/TiOx/SiO2/Si substrates. Nd substitution promoted random orientation with low (00l) diffraction peaks. The 1-μm-thick Bi3.25Nd0.75Ti3O12 film annealed at 750 °C exhibited a remanent polarization of 26 μC/cm2. Typical butterfly field-induced strain loops were obtained in the BNT film capacitors. The electrically induced strain is 8.4×10−4 under the bipolar driving field of 220 kV/cm. These results show that BNT is a promising candidate for use in lead-free thin-film piezoelectrics.

We introduce a novel variational approach for evaluating PTV image pairs and sequences in two and three dimensions. We combine a discrete non-differentiable particle matching term with a continuous regularization term. An advanced mathematical method guarantees convergence to a local minimum. The experimental evaluation shows that our variational method competes with three alternative approaches. We outline the potential of our method for further developments.

Low-temperature processing of Bi 4−x La x Ti 3 O 12 (BLT) thin films was investigated by chemical solution deposition using an excimer UV irradiation, and their ferroelectric properties, crystallinity and microstructure were characterized. BLT thin films were prepared on Pt(200 nm)/TiO 2 (50 nm)/SiO 2 /Si substrates by a spin-coating technique from alkoxide precursor solutions. The excimer UV irradiation onto as-deposited BLT thin films was highly effective in removing organic species of the gel films, leading to the decrease of the crystallization temperature and an increase of the crystallinity. The UV-processed BLT films started to crystallize at 550 • C and showed a high crystallinity and a high (117) preferred orientation for 600 • C-annealed films. BLT thin films prepared at 600 • C showed a homogeneous and dense microstructure with grain sizes of 200-300 nm. The excimer UV irradiation onto as-crystallized BLT thin films was also effective in improving the ferroelectric properties of the thin films. Bi 3.35 La 0.75 Ti 3 O 12 thin films prepared at 600 • C using excimer UV irradiation showed a well-saturated P-E hysteresis loop with a P r of 9.8 µC/cm 2 and E c of 78 kV/cm. Moreover, the Bi 3.35 La 0.75 Ti 3 O 12 thin films exhibited good fatigue endurance up to 10 10 switching cycles.

Neodymium-modified Bi 4 Ti 3 O 12 , (Bi,Nd) 4 Ti 3 O 12 (BNT) ferroelectric thin films have been prepared on Pt/TiO x /SiO 2 /Si substrates using metal-organic precursor solutions by the chemical solution deposition method. The BNT precursor films crystallized into the Bi layered perovskite Bi 4 Ti 3 O 12 (BIT) as a single-phase above 600 • C. The synthesized BNT films revealed a random orientation having a strong 117 reflection, whereas nonsubstituted BIT thin films exhibited a random orientation with strong 00l diffractions. Among Bi 4−x Nd x Ti 3 O 12 [x = 0.0, 0.5, 0.75, 1.0] thin films, Bi 3.25 Nd 0.75 Ti 3 O 12 thin films showed a well-saturated P-E hysteresis loop with the highest P r (22 µC/cm 2 ) and a low E c (69 kV/cm) at an applied voltage of 5 V. The Nd-substitution with the optimum amount for the Bi site in the BIT structure was effective not only for promoting the 117 preferred orientation but also for improving the microstructure and ferroelectric properties of the resultant films.

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