Electrostrictive effect in lead magnesium niobate single crystals

Transverse and longitudinal elastic strain have been measured for electric fields applied along the 〈100〉 direction in single crystals of lead magnesium niobate Pb(Mg1/3Nb2/3)03, using a bonded strain gauge technique. A quadratic electrostrictive relation holds between induced elastic strain and electric polarization for temperatures near the low-frequency dielectric maximum. The electrostriction coefficients are almost temperature independent with values Q11=2.50×10−2 m4/C2 and Q12=−0.96×10−2 m4/C2. To check the direct measurements, the hydrostatic Q coefficient was determined independently by measuring the pressure dependence of the dielectric permittivity. The value Qh =0.60×10−2 m4/C2 obtained is in good agreement with that calculated from the direct measurements.