Change in electromechanical properties of 0.9PMN : 0.1PT relaxor ferroelectric induced by uniaxial compressive stress directed perpendicular to the electric field

It was shown that the uniaxial compressive stress applied perpendicular to the electric field strongly changes the dielectric and electromechanical pr operties of relaxor ferroelectric 0.9PMN:0.1PT at temperatures around its d ielectric constant maximum, T-m. This includes: (i) a shift of the temperat ure of the electric field induced phase transition into the ferroelectric s tate and a depoling temperature to higher values which brings a large hyste resis in the material response to the electric field, and (ii) the symmetry breaking in the plane perpendicular to the direction of the electric field (3-axis). Using this symmetry breaking, from the ratio of the effective pi ezoelectric coefficients in the field biased state, d(32)/d(31), the size o f the micropolar regions at temperatures near T-m was estimated. (C) 1999 A merican Institute of Physics. [S0003-6951(99)04503-9].