Edward J. Staples

Czochralski single crystal growth of Sr.61Ba.39Nb2O6 for surface acoustic wave applications

Abstract Ferroelectric Sr.61Ba.39Nb2O6 (SBN) single crystals approximately 2 cm. in diameter and 5–6 cm. long have successfully been grown by the Czochralski technique. All the crystals were grown in the [001] direction in argon or oxygen, and it was found that the degree of difficulty of growth increased as the diameter of the crystals increased. Temperature dependence measurements on the poled Z-cut SBN crystals showed that this composition has temperature compensated orientations which make this material useful for surface acoustic wave devices.

An exploration of the limits of stability of the LiNb03 structure field with A and B site cation substitutions

Abstract A comparative study of crystal chemistry of LiM5+03, M = Nb5+ or Ta5+ was carried out. The limits of stability of the LiNb03 structure and the Tc appear to be controlled primarily by the sizes of the substitutional ions. The LiNb03 films were grown by the liquid phase epitaxy (LPE) technique, using the Li2 0-V2 05 flux. The Na-doped LiNb03 films showed a 30% reduction in the temperature coefficient of SAW velocity.

The zNose, a new electronic nose using acoustic technology

An array of sensors simulating the human olfactory response has become known as an electronic nose, or eNose. An eNose provides a vectorial image in N‐dimensional space (where N equals the number of sensors) of specific vapor mixtures containing possibly hundreds of different chemical species. Typically, eNoses have only a few sensors, produce responses that are not correlated, and have poor sensitivity. A new type of electronic nose, based upon fast chromatography and a single high‐Q acoustic sensor, solves these problems by stimulating a virtual sensor array containing hundreds of orthogonal sensors. Analysis of any odor is accomplished by serially polling this virtual sensor array or a spectrum of retention times. This paper will describe the acoustic technology as well as present results for applications involving important vapors associated with several commercial foods and beverages. Part per billion sensitivity has been achieved with volatile compounds and part per trillion sensitivity for semi‐vol...

Structural and dielectric properties in the system LiTaO3CaZrO3

Abstract A study of solid state reactions and dielectric properties has been made for the binary system LiTaO3ue5f8CaZrO3. Apart from the already known structures ilmenite and perovskite, one additional phase has been claimed for the compositions in the region Li.79Ca.21Ta.79Zr.21O3 to Li.30Ca.70Ta.30Zr.70O3. The dielectric measurements for the ilmenite solid solutions indicate that the ferroic transition temperature Tc decreases substantially with increasing amounts of CaZrO3 in LiTaO3. A phase-composition diagram for the LiTaO3ue5f8CaZrO3 system has been constructed on the basis of electric and X-ray diffraction studies.

Temperature coefficient of SAW velocity on epitaxial Li1−xNaxNbO3 thin films

Liquid‐phase epitaxy of doped Li1−xNaxNbO3 films on LiNbO3 has been performed. Sodium‐doped films show a 30% reduction in the temperature coefficient of surface acoustic wave velocity.

Surface acoustic wave transduction and poling in ferroelectric strontium barium niobate

Abstract The tetragonal Sr0.61Ba0.39Nb2O6 solid solution belongs to the tungsten bronze structural family and has a Curie temperature of approximately 70°C. Below the Curie temperature sponaneous polarization along the c-axis gives rise to piezoelectric coupling terms d31, d33 and d15. Interdigital electrode transducers photolithographically defined on the surface are used to generate and detect surface acoustic waves. Measurement techniques and results for SAW velocities and coupling constants for propagation on the z, x and (110) cuts will be presented in this paper. Above the Curie temperature the solid solution enters the paraelectric phase where application of an external electric field is used to induce polarization and generate surface acoustic waves. Y-cut, z-propagating surface waves are launched by poling the crystal with a spatially varying electric field. The Poling procedure is to apply a dc potential to the interdigital electrodes of the SAW transducers, the remainder of the crystal is unpol...