Relation between material property and crystal structure of perovskite ferroelectrics under high electric field

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The purpose of the present study was to develop a powder x-ray diffractometer which was capable of measuring under a high electric field, and to analyze structural changes in perovskite ferroelectrics under a high electric field.The x-ray diffraction intensities and diffraction angles of lead magnesium niobate(PMN)and lead ziconate titanate(PZT)ceramics were measured under the electric field up to 1.5kV/mm.The diffraction intensities and diffraction angles measured as a function of electric filed were analyzed with respect to the experimental results of electric field induced strain and piezoeiectric constant.The electric field induced change of diffraction angles, that is the strain of crystal lattice, were detected in PMN under a high electric field.The strain of crystal lattice was approximately consistent with the electrostrictive strain constant of ceramics.In the case of PZT,the change in the intensities of h00 and 001 diffractions were detected in place of diffraction angles.The change of intensities indicated that the reoriantation of ferroelectric 90 degree domains took place in the specemen.It was found that the electric field induced strain of PZT was the sum of the strain due to the piezoelectric effect and the strain due to the reorientation of ferroelectric 90 degree domains under a high electric field.