Microstructure observation of Pb(Mg1/3Nb2/3)O3-PbTiO3 single crystals by scanning electron microscopy

Abstract

Abstract Piezoelectric Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) single crystals (SCs) prepared by the Bridgman method on plates of 0.3 mm thickness were polarized by six different poling methods and their piezoelectric properties were analyzed. The sine wave AC-poled PMN-PT SC showed the best properties: a piezoelectric constant d 33 of 1920 pC N−1 and a free dielectric permittivity of 8050 without any spurious mode vibration. The plates were then broken to observe their microstructures by scanning electron microscopy. Clearly different vertical stripe and horizontal stripe microstructures were observed in the vertical direction of SCs. The differences in SC microstructures on the fracture surface were found to depend on the direction in which compressive and tensile stresses were applied. These results suggest that special attention should be paid when discussing the correlation between piezoelectric properties and SC microstructure, since the structure of piezoelectric SCs can vary depending on the sample geometry and pretreatment method.