Domain and antiferroelectric properties of Pb(Lu1/2Nb1/2)O3 single crystals and their superlattice structure

Abstract

In order to obtain antiferroelectric single crystals for understanding their structure and the physics and chemistry of the antiferroelectric phenomenon, antiferroelectric single crystals of Pb(Lu_1/2Nb_1/2)O₃ (PLN) were successfully grown. Two sets of superlattice reflections including the B-site atom ordering type reflection and the lead-ion antiparallel ordering type reflection were confirmed and distinguished from the X-ray diffraction patterns and transmission electron microscopy. Micro-domains and macro-domains were observed under the microscopes. The investigations were focused on the extinction angle, the angle of the domain wall and temperature dependence. The Curie temperature T_C was about 240 °C and 254 °C for [111]-oriented and [001]-oriented crystal plates respectively. The value of the energy density was calculated to be 3.65 J cm⁻³ for the [111]-oriented sample at 200 °C based on the double hysteresis loops with an electric field E_APP = 170 kV cm⁻¹ applied. All the above features, especially the high Curie temperature and high energy storage density, suggested that the PLN single crystals should be useful for large size energy storage devices that require a wider operation temperature range.