摘要
An eighth-order Landau–Devonshire theory is constructed to investigate the piezoelectric and electro–optic properties of tetragonal（1- x）Pb（Mg1/3Nb2/3）O3–xPbTiO3 single crystals（x = 0.38 and x = 0.4）. The dielectric stiffness coefficients of the Landau potential are obtained by fitting to the dielectric properties and the phase transition temperature between cubic phase and tetragonal phase. It is indicated that tetragonal（1- x）Pb（Mg1/3Nb2/3）O3–xPbTiO3 single crystals have the firstorder cubic-tetragonal phase transitions. The dielectric constants are in great agreement with the experimental results.The piezoelectric coefficients d33 and d31at room temperature are about 145 p C/N and-62 p C/N respectively which are smaller than that of（1- x）Pb（Mg1/3Nb2/3）O3–xPbTiO3 single crystals around the morphotropic phase boundary.Moreover, tetragonal（1- x）Pb（Mg1/3Nb2/3）O3–xPbTiO3 single crystals have the linear electro–optic coefficients rc =33.7 pm/V and rc = 28.8 pm/V for x = 0.38 and x = 0.4, respectively which are in accordance with the measurements.
An eighth-order Landau–Devonshire theory is constructed to investigate the piezoelectric and electro–optic properties of tetragonal（1- x）Pb（Mg1/3Nb2/3）O3–xPbTiO3 single crystals（x = 0.38 and x = 0.4）. The dielectric stiffness coefficients of the Landau potential are obtained by fitting to the dielectric properties and the phase transition temperature between cubic phase and tetragonal phase. It is indicated that tetragonal（1- x）Pb（Mg1/3Nb2/3）O3–xPbTiO3 single crystals have the firstorder cubic-tetragonal phase transitions. The dielectric constants are in great agreement with the experimental results.The piezoelectric coefficients d33 and d31at room temperature are about 145 p C/N and-62 p C/N respectively which are smaller than that of（1- x）Pb（Mg1/3Nb2/3）O3–xPbTiO3 single crystals around the morphotropic phase boundary.Moreover, tetragonal（1- x）Pb（Mg1/3Nb2/3）O3–xPbTiO3 single crystals have the linear electro–optic coefficients rc =33.7 pm/V and rc = 28.8 pm/V for x = 0.38 and x = 0.4, respectively which are in accordance with the measurements.
基金
Project supported by the National Natural Science Foundation of China(Grant No.51335002)
the Changzhou Science and Technology Project,China(Grant No.CJ20130022)
the Priority Academic Program Development of Jiangsu Higher Education Institutions,China
