This special issue of the IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control results from a combination of driving forces in existence over the past few years. One main motivator was the recent passing of Cecil Land, a past Chairman of the UFFC-S Ferroelectrics Committee and a leader in the research and development of transparent ferroelectric ceramic materials (PLZT) and related devices. It is entirely appropriate that a Special Issue of the UFFC Transactions be dedicated to honoring Cecil Land's memory. Another motivator for the preparation of this issue was the strong desire of the leadership of the UFFC-S to expand the publication activity of the UFFC Transactions into the area of Ferroelectrics. The UFFC-S and its predecessor organizations have, since the early 1960s, organized and put on many successful international symposia on the applications of ferroelectrics (ISAF). At the same time, they did not make a strong effort to encourage authors to publish their presentations at related symposia in the UFFC Transactions. In 1998, an extremely successful ISAF XI with a remarkable number of participants in attendance was held as part of a combined meeting of three different organizations; in Montreux, Switzerland. The UFFC-S leadership, at the time, hoped and expected that the creation of this Special Issue on Ferroelectrics would demonstrate to researchers in ferroelectrics that the UFFC-S had and continues to have a genuine interest in providing a publication outlet for papers in ferroelectrics. Several of the papers appearing in this special issue started as presentations at ISAF XI.
This Special Issue on Applications of Ferroelectrics contains 18 papers. The collection is divided into three groups:
The paper by Lahiri et al. is on the structural and dielectric properties of sol-gel derived barium-strontium-titanate thin films for which the variation of permittivitty with temperature and thickness was investigated. The paper by Tsai and Dey is an ab-initio study of the electronic structure and ground state energy of SrBi2Ta2O9 (SBT) in which the calculated electronic structure of SBT indicated the absence of the energy gap in the vicinity of the Fermi level. Another material that is analyzed is Sn2P2S6. In the paper by Maior et al., the effect of germanium doping on the pyroelectric and piezoelectric properties of the material is studied. A final paper concerned with a single crystal ferroelectric material is the paper by Rehrig et al., which reports the dielectric and electromechanical properties of barium titanate single crystals.
The paper by Friessnegg et al. reports the use of positron annihilation to analyze vacancy-related defects in thin films of lead-lanthanum-zirconate-titanate. The electrostrictive properties of another type of titanate, nanophase lead titanate, is reported in a paper by Akdogan et al. In this paper, the electrostrictive constants were calculated using the Landau-Ginzburg-Devonshire formulation and data from diffraction and thermal analysis. Ferroelectric glass ceramics represent a less common, but a potentially important, type of ferroelectric material. In a paper by Houng et al., a lead zirconate titanate glass ceramic is described in which SiO2 is an essential component of the material used to form the glassy phase, and PbO acts as a flux to reduce processing temperatures. Pressed and densified glass ceramics have d33 values of 26 pC/N and show the potential for use in applications of thick film transducers.
The paper by Koc et al. uses piezoceramic driving elements in a micromotor with a novel structure. The figure appearing on the cover of this issue was taken from this paper. The paper by Yao et al. is another paper concerned with miniature actuators, in this case, a stacked actuator for producing linear displacements. Two papers in this group are concerned with the nonlinear behavior of piezoelectric ceramics at high drive levels. One paper is by Alberada et al., and the other is by Garcia et al. A paper by Howarth et al. reports on the acoustic evaluation of 1-3 piezocomposite SonoPanel™ materials used for underwater acoustic applications. Another paper by Ritter et al. describes the capabilities of PZN/PT single-crystal composites for use in ultrasonic transducer applications. An additional transducer paper is the paper by Ramos et al. This paper deals with improving the transient response of NDE transceivers using selective damping and tuning networks.
A different but important application of ferroelectric materials is involved with memory devices. The paper by Sheikholeslami et al. is a paper concerned with modeling the circuit behavior of ferroelectric capacitors used in integrated-circuit memory devices. Another paper related to memory device applications of ferroelectric materials is the paper by Shin et al. This paper studies the feasibility of using thin PZT films as a data storage medium and reports the observation of written features as small as 100 nm, indicating a great potential for high-density data storage.
Editors
Ahmad Safari, Member, IEEE
Allen Meitzler, Life Fellow, IEEE