Operation of multiple 90° switching systems in barium titanate single crystals under electromechanical loading

Hysteresis evolution of a 5 x 5 x 2 mm(3) barium titanate single crystal during a combined electromechanical loading sequence reveals incomplete switching characteristics and a considerable disproportion of slope gradients at zero electric field for the measured polarization and strain hysteresis curves. A likely cause for the disproportion of gradients is the cooperative operation of multiple 90 degrees switching systems by which polarization-free strain changes are induced. In addition, a theoretical study indicates that the presence of depolarization fields generated from the unshielded boundaries and/or incompatible domains within the crystal can have a substantial influence on the polarization measurement in the loading direction. (c) 2007 American Institute of Physics.