Spatial distributions of polarization and space charge in tin-substituted lead zirconate titanate ceramics using laser intensity modulation method (LIMM)

Abstract

A new method for measuring the spatial distribution of combined polarization and space charge in poled polymer electrets was recently developed. The technique, called the Laser Intensity Modulation Method (LIMM), was modified in the present study in order that it could be used with ferroelectric ceramic samples having thicknesses of the order of 1 mm rather than the tens of micrometers found in conventional polymer films. PZT ceramics with a high Sn content and with compositions close to the Zr phase boundary were studied. The effects of poling conditions on polarization and space charge distributions in the two ferroelectric phases were examined. The polarization distributions were highly nonuniform, being flat in the central regions and diminishing strongly in the regions close to the electrodes. This was true even in samples poled to saturation. Large amounts of space charge were observed in the central regions. Pyroelectric coefficients and spontaneous polarizations were also measured.