Electrostrictive effect in lead magnesium niobate single crystals

Abstract

Transverse and longitudinal elastic strain have been measured for electric fields applied along the 〈100〉 direction in single crystals of lead magnesium niobate [Pb(Mg_1/3Nb_2/3)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 Q_h =0.60×10⁻² m⁴/C² obtained is in good agreement with that calculated from the direct measurements.