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Imaging of 180 Ferroelectric Domains in LiTaO3 by Means of Scanning Electron Microscopy

The 180° ferroelectric domains, engineered through field poling in single crystalline LiTaO 3 were directly observed by means of scanning electron microscopy (SEM) on its polished polar surfaces without metal coating. Two kinds of domain images, the brightness-contrast image and topographic-boundary image, were found with slow scan rate under the condition of a cathode voltage of V 0 = 3 to 5 kV and a probing beam current of I b = (4 to 20) × 10 -11 A. They appeared at the initial and subsequent frames of scanning, respectively. The formation of these two kinds of images is explained as pyroelectric and piezoelectric effects which originated from the beam electron heating and the charge accumulation on the top surface of a LiTaO 3 crystal.