Phase transition behavior and defect chemistry of [001]-oriented 0.15Pb(In1/2Nb1/2)O3-0.57Pb(Mg1/3Nb2/3)O3-0.28PbTiO3-Mn single crystals

Abstract

The ferroelectric single crystals 0.5 mol. % Mn-doped 0.15Pb(In1/2Nb1/2)O3-0.57Pb(Mg1/3Nb2/3)O3-0.28PbTiO3 (PIMNT-Mn) with rhombohedral perovskite structure were grown by a modified Bridgman method. Dielectric performance analysis reveals that the as-grown PIMNT-Mn single crystals exhibit complex dielectric behavior after polarization, in which the dielectric constant depends on frequency apparently around the ferroelectric phase transition temperatures TR-M and Tm. The temperature and electric-field induced ferroelectric phase transitions were investigated by the temperature dependent unipolar strain curves. The electric-field induced discontinuous ferroelectric phase transitions at elevated temperatures exhibit first-order like phase transition character. The converse piezoelectric constant (d33), maximum strain value (Smax%), and longitudinal electrostrictive coefficient (Q) increase considerably when the temperature approaches the ferroelectric phase transition temperatures TR-M and TM-T. The complex impedance curves (Z″-Z′) present typical semicircle shapes from 425 °C to 550 °C. The activation energy calculated by the Arrhenius law is 0.86 eV, indicating that the high-temperature conduction mechanism is dominated by the extrinsically formed oxygen vacancies.