Tensile stress induced depolarization in [001]-poled transverse mode Pb(Zn1/3Nb2/3)O3 -(6-7)%PbTiO3 single crystals

Abstract

This paper investigates the effects of electrically induced and direct tensile stress on the deformation and dielectric properties of Pb(Zn 1/3Nb2/3)O3-(6-7)%PbTiO3 single crystals of [110]L × [001]T cut by using a unimorph sample and a four-point-bend (FPB) sample, respectively. The results show a dip in tip displacement for the unimorph sample at sufficiently high electric field parallel to the poling field direction and a sudden rise in capacitance for the FPB sample at sufficiently high tensile stress in the [110] crystal direction, respectively. These phenomena are attributed to the tensile stress induced rhombohedral-to-orthorhombic phase transition and associated depolarization events in the crystal. For the said crystal cut, the obtained tensile depoling stress is in the range of 15-20 MPa. The present work furthermore shows that the occurrence of tensile stress-induced depolarization is possible even when the direction of the applied electric field is parallel to the poling field direction, as in the unimorph sample examined. © 2011 American Institute of Physics.