Defect dipole evolution and its impact on the ferroelectric properties of Fe‐doped KTN single crystals

Abstract

The ferroelectric and piezoelectric properties of doped potassium tantalum niobate crystals with different Fe doping amounts and the adjustability of the properties are investigated. The hysteresis loops and current density curves show that the defect dipoles have an obvious effect on domain reorientation, and the effect decreases with increasing doping amount. The ferroelectric and piezoelectric properties can be adjusted via the defect dipoles, and the adjustability is reduced with increasing doping amount. A change of the doping amount leads to defect dipole structure evolution in the crystals, in which the defect dipoles transform from a polar structure to a nonpolar structure, which is the reason for the transition of the domain reorientation determined by the defect dipoles. This result has proved that introducing defects is an effective way to improve and regulate perovskite properties, and the doping amount is one of the important factors controlling the defect dipoles.

Enhanced Electrocaloric Effect Induced by the Electric-Field-Generated Like-Multiphase Coexistence in Anisotropic KTa1–xNbxO3 Single Crystals

“…The results of XRD are shown in Figure d. According to the diffraction angles (2θ) of anisotropic planes, the lattice constant a is calculated (∼3.99 Å), which is consistent with previous reports . This suggests that the impact of inaccurate cutting on the performance of the anisotropic EC properties is avoided.…”

“…According to the diffraction angles (2θ) of anisotropic planes, the lattice constant a is calculated (∼3.99 Å), which is consistent with previous reports. 23 This suggests that the impact of inaccurate cutting on the performance of the anisotropic EC properties is avoided. The temperature dependence of relative permittivity (ε r ) and dielectric losses (tan δ) of the three samples is shown in Figure 1e.…”

Effect of Ni doping on the electro-optic property in K(Ta0.6Nb0.4)O3 films

“…24) The ferroelectric to paraelectric phase transition temperature, and hence the dielectric, ferroelectric and EO properties can be modulated by tuning the composition ratio of Ta/Nb. 23,25,26) However, the growth of high quality KTN films required for the state of the art thin-film-based plasmonic EO devices remains challenging. Our previous work confirmed that epitaxial (001) KTN films with near stoichiometric composition possess a linear EO response and large EO coefficient of 49 pm V −1 among the reported values.…”

Cu-Doping-Modified Order State, Ferroelectric Property, Multiscale Inhomogeneities, and Local Structure in the Relaxor KTa1–xNbxO3 Crystal

“…However, highly doped Fe ions can reduce the dielectric permitivity because of the excessive “locked” size and direction of polarized regions . In addition, doping Fe also affects the polarization–electric field loops through controlling the concentration of Fe ions . Mn doping can enhance the piezoelectric properties of KTN owing to the enhanced IMI, resulting in weaker dipole correlation and increased local polarization .…”