Adaptive behavior of 0.9PMN-0.1PT ceramics

The 0.9PMN-0.1PT longitudinal strains induced by a quasi-static electric field (20 mHz frequency with a 0 to 0.5 kV/mm amplitude) exhibit a nonlinear behavior as a function of the compressive stress (-5 to -30 MPa) and can be well fitted by a polynomial relation of the strain as a function of the stress and the electric field: x/sub T/(E,X)=/spl Sigma//sub i/(/spl Sigma//sub j/, M/sub ij/, E/sup j/).X/sup i/ with i=0...2 and j=0...3, for which the coefficients M/sub ij/ directly depend on the temperature. Consequently, this shows that the dynamic elastic compliance of the material is a function of the electric field, compressive stress and temperature. These dependencies can be attributed to the growth of compliant polar clusters distributed in a paraelectric matrix, induced by decreasing temperature or increasing electric field, and inhibited by the application of a compressive stress. Therefore, in conclusion, 0.9PbMg/sub 1/3/Nb/sub 2/3/0/sub 3/-0.1PbTiO/sub 3/ bulk ceramics can be considered as adaptive materials.