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The piezoelectric d coefficients of oriented (1-x)Pb(Zn/sub 1/3/Nb/sub 2/3/)O/sub 3/-xPbTiO/sub 3/ single crystals for x = 0.045 and x = 0.08 (PZN-4.5%PT and PZN-8%PT) have been measured as functions of DC bias field and frequency using a Zygo laser interferometer system. The d coefficients decreased as the DC bias was increased, perhaps because of domain wall clamping due to the bias field. The d coefficients were also found to decrease with the increase of frequency; this frequency dependence decreased at sufficiently large bias fields. High d/sub 15/ values (/spl sim/2800 pC/N for PZN-4.5%PT and /spl sim/3300 pC/N for PZN-8%PT) were measured, which may make these oriented crystals promising candidates for high performance shear transducers.

Polarization and Raman measurements, in KTa1-XNbX O3 (KTN), have shown the existence of precursor effects many degrees above the transition. These effects are due to the formation of polar nanoregions, or clusters, which also explain the departure of the susceptibility from its Curie-Weiss dependence at high temperature. It was also shown through ultrasonic measurements at high temperatures and concentrations that the clusters behave as dynamical polar fluctuations resulting in a softening of C11 with a (T-Tc)-0.5 dependence. In order to investigate the coupling between these polar fluctuations and the elastic strains of the solid, measurements of the elastic constants have been made for applied DC fields in the direction of propagation. Results are presented for C 11 and C44 in concentrations up to 16% Nb. These measurements have been extended through the transition where evidence has been found to support the existence of three transitions even at the lowest concentration

A microstripline pulse field system that allows the switching speed of high coercivity magnetic media to be measured with pulse widths t>or=0.64 ns is discussed. The results for gamma Fe/sub 2/O/sub 3/ are in good agreement with the previous work of Thornley and Williams (1974). A DC bias field H/sub B/ was added to the pulse field to allow the high coercivity samples to be switched from saturation to zero remanence and the results analyzed in terms of the switching constant S/sub w/. At H/sub B/=400 Oe, S/sub w/(Co- gamma Fe/sub 2/O/sub 3/)=158 ns-Oe; at H/sub B/=700 Oe, S/sub W/ (barium ferrite)=135 ns-Oe; at H/sub B/=720 Oe, S/sub W/ (metal particle)=84 ns-Oe. The value of S/sub W/ increased with decreasing bias field, particularly for barium ferrite, indicating that in zero bias barium ferrite tapes it would be a factor of three slower than metal particle tapes. >