Role of lower valent substituent-oxygen vacancy complexes in polarization pinning in potassium-modified lead zirconate titanate

Abstract

The dependence of polarization switching on thermal histories has been investigated for K1+-modified lead zirconate titanate (PZT) ceramics by Sawyer–Tower polarization methods. It was found that double-loop-like polarization characteristics in the aged condition could be reversed to normal single loop polarization characteristics by quenching specimens from above the ferroelectric phase transition temperature. However, the P–E curves reversed back to double-loop-like characteristics after reaging specimens at elevated temperatures. Excess oxygen vacancies in La3+-modified PZT were not found to result in double-loop-like polarization hysteresis, whereas excess oxygen vacancies in K1+-modified PZT did. These results provide evidence for role of K1+-oxygen vacancy complexes in polarization pinning.

Evidence of temperature dependent domain wall dynamics in hard lead zirconate titanate piezoceramics

“…18,19 The pinching of the loop is attributed to the existence of pinning centers, which are formed by the presence of oxygen vacancies associated to the acceptor ion. [18][19][20][21] Fig. 4 shows the hysteresis loop of hard PZT at 200 K and at 300 K for the same maximum electric field.…”

Antiferroelectric-like properties and enhanced polarization of Cu-doped K0.5Na0.5NbO3 piezoelectric ceramics

“…Similar P-E loops have been reported for ferroelectrics that contain oriented polarized defects. 11,12 Fig. 2(b) also reveals that a strong internal bias field (E ib ¼ 0.9 kV/mm) is established in the KNN10 ceramic during poling.…”

“…The crucial role played by the migration kinetics of point defects has been demonstrated in Al 3þ -doped BaTiO 3 ceramics, 10 where the Al 3þ -doping leads to lattice shrinkage and suppresses the FE aging effect at high level doping. Moreover, double P-E loops have also been reported in some acceptor-doped ferroelectrics without aging, such as in K þ -doped PbZr x Ti 1Àx O 3 (PZT) 11,12 and Cu 2þ -doped K 0.5 Na 0.5 NbO 3 (KNN) ceramics. 13 This phenomenon has been explained on the basis of the high mobility of defect dipoles, which could reorient easily after the formation of domain patterns.…”

“…13 This phenomenon has been explained on the basis of the high mobility of defect dipoles, which could reorient easily after the formation of domain patterns. [11][12][13] Accordingly, aging is not required for the ceramics to exhibit double P-E loops. In the present work, we studied the P-E loops and dielectric aging behaviors of KNN ceramics with Cu doping.…”

Relaxor-to-Ferroelectric Crossover and Disruption of Polar Order in “Empty” Tetragonal Tungsten Bronzes

“…[50][51][52][53][54] Thermal annealing above T C or applying 'de-aging' or fatiguing bipolar excitation cycles of sufficient field can reverse the mechanisms responsible for aged, defect-mediated pinched P-E loops in "normal" ferroelectrics. [55][56][57] Such measurements were performed on Ba 4 La 0.67 Nb 10 O 30 (see ESI Figures S12-S15 for details).…”