Giant shape memory and domain memory effects in antiferroelectric single crystals

We report irreversible and reversible antiferroelectric-ferroelectric phase transitions, shape memory and domain memory effects in (Pb,La)(Zr,Sn,Ti)O-3 antiferroelectric tetragonal single crystals. We find that electric-field-induced antiferroelectric to ferroelectric phase transition is an irreversible process at temperatures below the depolarization temperature (similar to 50 degrees C), and achieves a giant shape memory strain value of 0.70% at room temperature. With the help of an in situ polarized light microscope, we discover a reversible phase transition between antiferroelectric and ferroelectric phases and a domain memory effect during electric field cycling above the depolarization temperature. In addition, single crystal X-ray diffraction results reveal that field-induced transformations between incommensurate antiferroelectric and commensurate ferroelectric modulations enable the emergence of shape and domain memory effects. A physical picture is proposed to explain these phase-transformation-mediated memory effects. Their discovery is expected to stimulate a systematic research upsurge of domain engineering and structure-property relationships in the quest for developing new antiferroelectric or ferroelectric devices.