Interferometric measurements of electric field-induced displacements in piezoelectric thin films using single-beam and double-beam optical detection schemes are reported. It is shown that vibrational response measured with a single-beam interferometer includes a large contribution of the bending motion of substrate. Therefore, it is difficult to apply single-beam technique for piezoelectric measurements in thin films. To suppress the bending effect a high-resolution double-beam interferometer is proposed. The sensitivity of the interferometer is significantly improved in comparison with previously reported system. The interferometer is shown to resolve small displacements without using a lock-in technique. An example of the interferometric capabilities is demonstrated with experimental results on electric field, frequency, and time dependences of piezoelectric response for quartz and Pb(Zr,Ti)O3 thin film.

The piezoelectric response of silicon diaphragms covered with sputter-deposited PbZr 0.45 Ti 0.55 O 3 (PZT) films has been investigated in view of their application in ultrasonic micro-actuators. The behaviour of resonance frequencies and quasistatic deflections has been studied as a function of membrane thickness and d.c. bias. The total stress in the films and the piezoelectric constant, d 31 , have been derived by means of two different methods. The results are consistent with direct strain measurements by optical interferometry and with bulk ceramic values of identical composition.

For the first time we have characterized a micromotor driven by a piezoelectric PZT (PbZr x Ti 1-x O 3 ) thin film. Sputter and sol-gel techniques have been applied for the deposition of the PZT films onto a silicon stator membrane, which was 20 to 30 µm thick and had a diameter of 4 mm. The amplitudes of the membrane deflections have been measured by means of laser interferometry. They are as large as 800 nm/V at the first resonance (26 kHz), and 60 nm/V at 1 Hz. This is one order of magnitude larger than previously reported for a ZnO activated device of similar geometry. The operation of the motor was obtained at 1 to 3 V rms , with speeds of up to 200 rpm at 1.1 V rms and torques of 35 nN·m at 2.5 V rms and 1 mN force between rotor and stator. In comparison with the conceptually identical ZnO version published by Racine et al. this is an improvement by a factor of 3 in speed per volt. Taking into account the linear increase of the torque with the stator vibration frequency, the torque per voltage is a factor two higher. A long time test of 100 h showed no degradation of the motor performance.

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The difference in the crystal structure and growth kinetics of microtubes formed from l- and d-enantiomers of diphenylalanine dipeptide is investigated both experimentally and theoretically by computer simulation. The microtubes of l- and d-enantiomers grown simultaneously and under identical experimental conditions possess different crystallographic space groups, have essential difference in sizes, and demonstrate different growth kinetics. Computer simulation by molecular mechanics methods revealed a fundamental difference in the interaction between structural units of microtubes of different chiralities. A model describing chirality-dependent growth of microtubes is proposed.