Defect Control and Properties in Bismuth Layer Structured Ferroelectric Single Crystals

Abstract

The static and dynamic behaviors of ferroelectric domains are the underlying basis of various functional properties of ferroelectric materials, such as dielectricity, piezoelectricity, ferroelectricity, and electro-optic and acoustic-optic effects. Since the performance of ferroelectric devices is governed by these behaviors, various techniques for enhancing device performance have been widely investigated with the aim of controlling ferroelectric domains [19,20,88,109]. Such control, however, is often prevented not only by a large leakage current but also by undesirable behaviors such as domain clamping [16,73,95], fatigue [17,98], aging [63,68], imprinting [110], and depoling [98]. Ferroelectric devices thus suffer from degraded polarization and poor reliability due to insufficient control over ferroelectric domains. It is considered that the poor polarization properties, fatigue, and aging, etc. are governed by the interaction between defects and ferroelectric domains.Bismuth layer-structured ferroelectrics (BLSFs) have attracted much attention because of their high Curie temperature (T C ) and larger spontaneous polarization (P s ). The relation between crystal structure and ferroelectric properties of BLSFs has been widely investigated because of their anisotropy of ferroelectric polarization [10,22,113]. In the crystal structure of BLSFs, perovskite layers (A mÀ1 B m O 3m+1 ) are sandwiched between Bi 2 O 2 layers, where m is the number of BO 6 octahedral layers with A-site cations in the perovskite layers, as shown in Fig. 14

Bright Upconversion Emission, Increased Tc, Enhanced Ferroelectric and Piezoelectric Properties in Er‐Doped CaBi4Ti4O15 Multifunctional Ferroelectric Oxides

“…If possible, the Er 3+ ‐doped CBT oxide could be sputtered to a P + ‐Si substrate to fabricate the high efficient electroluminescent film . Owing to its relatively low melting point, these BLSFs could be also grown to transparent vitroceramics or single crystals for studying the effects of optical‐electrical coupling and laser applications . It should be noted that there are still some approaches to optimize the emission properties of CBT_Er_ x .…”

“…It is known that BLSFs are also important dielectric, ferroelectric, and piezoelectric materials that are widely used for high‐temperature sensors, thin‐film memory devices, and lead‐free piezoelectric resonators . As a member of bismuth‐layered pseudo‐perovskites, CBT is one of the candidates for application in dielectric, ferroelectric, piezoelectric and pyroelectric devices, filters, resonators, and micro‐electro‐mechanical systems …”

“…This means that leakage current problems of the CBT system can be improved by introducing Er ions . With higher T c and lower dielectric loss tan δ, CBT_Er_ x ceramics can be regarded as a good candidate material for high temperature piezoelectric sensor applications …”

Upconversion luminescence, ferroelectrics and piezoelectrics of Er Doped SrBi4Ti4O15

“…58,59 Owing to its relatively low melting point, these BLSFs could be also grown to transparent vitroceramic or single crystal for optical-electrical coupling studies effects and laser applications. 60,61 It should be noted that there are still some approaches to optimize the emission properties of SBT_Er_x. Emission intensity could be moderated by introducing electric field, 62 plasma-enhanced process 25 and rational design special structure, 26 …”

“…[1][2][3][4]61 As a member of BLSFs, SBT is one of the candidates that have potential application in the dielectric, ferroelectric and piezoelectric devices. 50,54,61,68 Studies on dielectric properties of the Er doped samples have also been carried out. Figure 4(a) shows temperature dependence of dielectric constant and dielectric loss at 1MHz frequency as a function of Er 3+ content.…”