Electronstriction in the lead magnesium niobate-lead titanate-barium titanate system

”The lead magnesium niobate - lead titanate - barium titanate (PMN-PT-BT) system was investigated in terms of its electrostrictive and dielectric properties. The PT content was held constant at 5, 15, 30, or 50 mol%, as the BT concentration was varied from 0-40 mol% with PMN making up the difference. A method was devised using a linear variable differential transformer (lvdt) to measure the small strains associated with electrostriction, which when combined with polarization results, yields the electrostriction coefficients. Increases in BT content were expected to decrease the temperature of the maximum dielectric constant, Kmax. This was found to be true to the extent that 5 mol% additions of BT reduced the temperature by as much as 40°C. However, the BT additions also resulted in a significant decrease in Kmax. Without further results, the possibility that BT additions would outperform its predecessors in electrostrictive applications is difficult to say. On a more positive note, the increased BT content increased the electrostriction coefficient. This study also supported the result that increased PT content within this ternary system resulted in larger maximum strains. This increase was also correlated to higher peak temperatures within the families of compositions. Consistent with theory, electrostrictive results showed that additions of BT added to the disorder in the PMN perovskite crystal structure --Abstract, page iii