Electrostrictive coefficients of 0.9Pb(Mg1/3Nb2/3)O-3-O.1PbTiO(3) relaxor ferroelectric ceramics in the ferroelectricity-dominated temperature range

Abstract

Polarization and strain induced by unipolar electric fields (P-uni, S-uni) as well as those induced by bipolar electric fields (P-bi, S-bi) were measured in 0.9Pb(Mg1/3Nb2/3)O-3-0.1PbTiO(3) relaxer ferroelectric ceramics in the temperature range of -50 degrees-90 degrees C to observe the phase transition in this region and calculate the electrostrictive coefficients from the purely electric-field-induced polarization and strain. By considering both the electrostrictive component (P-uni, S-uni) and the piezoelectric component (P-uni, S-uni), it is shown quantitatively how the transition occurs from pure electrostrictive to partially piezoelectric properties across the phase transition range. P-uni represents unmixed electric-field-induced polarization, while P-bi represents the summation of P-uni and P-r. Similarly, S-uni represents unmixed electric-field-induced strain, while S-bi represents the summation of S-uni and S-r. The effective electrostrictive coefficient (Q(eff)) is calculated even in the ferroelectric region far below the phase transition temperature using S-uni and P-uni which are purely electric field induced. Q(eff) significantly increases as the temperature decreases below the phase transition temperature, which was attributed to the decreased rattling space of B-site atoms.