Defect Control for Large Remanent Polarization in Bismuth Titanate Ferroelectrics –Doping Effect of Higher-Valent Cations–

Abstract

The effects of concentration and distribution of defects controlled by quenching and doping of higher-valent cations on the ferroelectric properties of dense Bi4Ti3O12 ceramics were investigated. The remanent polarization (P r) of non-doped ceramics quenched from 800°C (above the Curie temperature) was twice as large as those of samples subjected to slow cooling to 25°C and quenched from 600°C (below the Curie temperature). These results imply that domain pinning by defects dominates the polarization properties. The incorporation of vanadium and tungsten into Ti site significantly reduced the influence of domain pinning, resulting in a very large 2P r of over 40 µC/cm2.

Investigation of site selectivity of lanthanum in SrBi4Ti4O15 ceramic by structural, dielectric, ferroelectric and conduction behavior

“…The variation of P r and E c on La content (x) could be explained in terms of the changing oxygen vacancy concentration in the system. It is reported that oxygen vacancies are created due to bismuth loss, and under high electric fields the mobile oxygen vacancies can assemble at the lowest energy domain walls and thereby hinder polarization switching due to domain pinning [37]. At higher La content x [ 0.15, the decrease in P r was attributed to the relaxation in structural distortion as noted from X-ray and Raman spectroscopy study.…”

Fabrication and Study on One-Transistor-Capacitor Structure of Nonvolatile Random Access Memory TFT Devices Using Ferroelectric Gated Oxide Film

“…[9][10], and the 2Pr value was smaller and the Ec value was larger than those reported in [31]. Based on above results, it was found that the simultaneous substitutions for B-site are effective to derive enough ferroelectricity by accelerating the domain nucleation and pinning relaxation caused by B-site substitution [32][33][34][35]. According to pervious study, the Bi 4 Ti 3 O 12 materials exhibit high leakage current and domain pinning properties because of the defects such as bismuth and oxygen vacancies.…”

“…In addition, the B-site substitution by high-valent cation was mainly the compensation for the defects. These defects caused by the fatigue phenomenon and strong domain pinning [37][38][39][40].…”

Enhanced Dielectric and Ferroelectric Properties of Donor (W6+, Eu3+) Substituted SBT Ferroelectric Ceramics

“…[101] reported a remarkable improvement in ferroelectric properties in the Bi 4 Ti 3 O 12 ceramic by adding higher valent cation, V 5+ at the Ti 4+ site. Recently, significantly large P r value has been reported for W-substituted BIT sintered sample [102]. It has also been reported that cation vacancies generated by donor doping make domain motion easier and enhance the ferroelectric properties [103].…”