PHASE-TRANSITION, DIELECTRIC AND ELECTROSTRICTIVE BEHAVIORS IN (1-X)PYN-XPMN

A system of (1 - x)Pb(Yb1/2Nb1/2)O-3 (PYN)-xPb(Mg1/3Nb2/3)O-3 (PMN) (0 less than or equal to x less than or equal to 1) has been investigate d with regard to its phase transition, densification, and dielectric a nd electrostrictive properties. According to the XRD study, a crystal structure transformed from orthorhombic to pseudocubic at approximatel y x = 0.22. The superlattice peaks were gradually weakened with increa sing x, and disappeared above x = 0.22. Increasing x led to an increas e in the maximum dielectric constant and a decrease in transition temp erature over the entire composition range. As a result of P-E hysteres is loops, successive phase transitions of ferroelectric-antiferroelect ric-paraelectric were observed to occur in the range of 0.18 less than or equal to x less than or equal to 0.25 with increasing temperature, while the direct transition into the paraelectric region was found to take place for x greater than or equal to 0.3. From the field-induced strain measurement, high electrostrictive coefficients 7.3-8.2 x 10(- 2) (m(4)/C-2), were determined in the PYN-rich range (x less than or e qual to 0.1). Based on the results, a phase diagram of the system was constructed with variations in x and temperature.