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 properties of relaxor ferroelectric 0.9PMN:0.1PT at temperatures around its dielectric constant maximum, T-m. This includes: (i) a shift of the temperature of the electric field induced phase transition into the ferroelectric state and a depoling temperature to higher values which brings a large hysteresis 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 piezoelectric coefficients in the field biased state, d(32)/d(31), the size of the micropolar regions at temperatures near T-m was estimated. (C) 1999 American Institute of Physics. [S0003-6951(99)04503-9].