Strontium Bismuth Titanate [SrBi
4Ti
4O
15 (SBT)] is a well-known member of the bismuth oxide layer structure ferroelectric (BLSF) material and has the potential for application in sensors, actuators, high-temperature piezoelectric applications, and memory storage devices (ferroelectric NvRAM) [
1,
2]. The SBT ceramic has high Curie temperature (T
c = 530 °C) but the piezoelectric properties are comparatively lesser than that of a lead based system [
3]. It has orthorhombic symmetry with space group
A2
1
am at room temperature and transforms to tetragonal space group
I4
/mmm above the transition temperature [
4]. The major drawback with the SBT material is the volatilization of bismuth during the sintering process at high temperature in solid state reaction method. The bismuth volatilization leads to the formation of oxygen vacancy in order to maintain the charge neutrality. Oxygen vacancy might be preferably present in the vicinity of the Bi ions which could dramatically decreases the properties [
5]. This oxygen vacancy plays an important role in determining the fatigue property of a ferroelectric material. Chu et al. [
6] reported that fatigue is caused by the diffusion of oxygen vacancies to the domain walls and subsequently pinning the domain walls. Furthermore, previous studies have found that the oxygen vacancy is the dominant point defect in oxide feroelectric materials [
7]. It has also been regarded as the cause of many detrimental effects such as pinning domain walls, screening the electric field near the space charge region, impeding the displacement of the Ti
4+ ion, trapping charge carriers, and enhancing leakage current [
8‐
10]. This oxygen vacancy is also responsible for increase in conductivity of the material. For industrial application as memory, it is necessary to obtain materials with low dielectric loss, low conductivity and high fatigue properties. In order to minimize the drawback associated with oxygen vacancy, as well as to tailor the ferroelectric properties of BLSFs, many studies have been reported on A and/or B-site substitutions in SBT. Recently, efforts have been made to enhance the properties of layer perovskites by substitution the Bi
3+ by alternative cations. Moreover, substitution of stable trivalent lanthanide ions for volatile bismuth ions was effective for suppressing oxygen vacancy concentration and increasing the chemical stability of the Perovskite layers which strongly affect the electrical properties [
11,
12]. On the other hand, some researchers found that among the lanthanoidal dopants, La
3+ (Lanthanum) is frequently added to other bismuth-based layer perovskite ceramics in order to lower its tanδ value with decrease in conductivity, improvements in ferroelectric properties, and improved fatigue resistance [
13‐
15]. Chakrabarti et al. [
16] observe that La
3+ substitution for Bi
3+ at the A-site in BaBi
4−xLa
xTi
4O
15 ceramic results in a well defined relaxor behavior with a reduction in DC conductivity. Khokhar et al. [
17] reported the enhancement of ferroelectric properties of La doped BBT ceramic up to 20 % of La doping. There are a few reports in the literature on La substituted SrBi
4Ti
4O
15 ceramics. It has been reported by Zhu et al. [
18] that, the substitution with La
3+ in the bulk SBT system produces a structural distortion. Chen et al. [
19] reported apparently much higher level of Lanthanum ion substitution in SBT materials and determined the lattice distortion and internal stress. In these earlier studies, the structural properties of La modified SrBi
4Ti
4O
15 with a wide variation are described without any supporting evidence from dielectric and electrical study. Therefore, it motivates us to further investigate the dielectric, ferroelectric, impedance and conductivity behavior of La
3+ modified SBT ceramics and to correlate the observed changes with the induced structural effect.