ORIENTATION DEPENDENCE OF DIELECTRIC AND PYROELECTRIC PROPERTIES OF 0.65Pb(Mg_1/3Nb_2/3)O₃- 0.35PbTiO₃ SINGLE CRYSTAL

Abstract

Samples of 0.65 Pb ( Mg 1/3 Nb 2/3) O 3-0.35 PbTiO 3 single crystal cut in three orientations <001>, <110>, <111> were supplied by H. C. Materials Corporation, Urbana, Illinois, U.S.A. The dielectric constant was first measured for these three samples with different orientations. It shows the samples are of high quality. Then we observed the hysteresis loops at different temperatures for these samples. From hysteresis loops we obtained the remnant polarization as a function of temperature. It is found that the remnant polarization changes with temperature rapidly in the temperature region from 80°C to 130°C. The displacement current without sustained applied electric field on it that is supposed to be proportional to the pyroelectric coefficient in different orientation was measured by a Picoammeter under no applied electric field and the comparison of the displacement current density with the pyroelectric coefficient was presented.