Domain Structure and Fatigue Behavior of La³⁺‐Doped SrBi₂Ta₂O₉ Thin Films

Abstract

Ferroelectric SrBi 1.4 La 0.6 Ta 2 O 9 (SBLT) thin films were grown onto Pt/Ti/SiO 2 /Si substrates by pulsed-laser deposition. With the aid of X-ray diffractometry, piezoresponse scanning probe microscopy, and ferroelectric-property measurements, a correlation between microstructure, as well as domain structure and ferroelectric properties, was established. Excluding the effect of preferential orientation on ferroelectric properties, the increase in remanent polarization was attributed to distortion of the perovskite-like sublattice and atom displacement. Despite the coinstantaneous observation of a 901 domain and slight fatigue behavior in the SBLT films, the 901 domain-wall clamping did not seem to account for the fatigue in the SBLT films. Instead, strain-stress aggravation of the SBLT sublattice, due to the substitution of La 31 into Bi 31 sites, decreased the self-regulated flexibility of the (Bi 2 O 2 ) 21 layers and caused fatigue in the SBLT.

Metal-Organic Chemical Vapor Deposition of Ferroelectric SrBi2Ta2O9 Films from a Fluorine-Containing Precursor System

“…Postdeposition annealing of Sr−Bi−Ta deposited films at 450 °C was performed in the temperature range 600−800 °C under O 2 flow. Thermal treatments at 650 and 700 °C cause the formation of both SBT and nonstoichiometric fluorite phases. , By contrast, annealing at 800 °C under O 2 flow leads to random oriented polycrystalline SBT films without cracks, in accordance with the GIXRD pattern and SEM micrograph (Figure ). Figure shows AFM images of films (a) as-deposited at 450 °C (roughness ∼ 4 ± 1 nm) and (b) annealed at 800 °C (roughness ∼ 13 ± 1 nm).…”

Microstructural Modeling of Ferroelectric Materials: State of the Art, Challenges and Opportunities

“…For every chemistry, a better understanding on the degradation and fatigue mechanisms of ferroelectric materials, caused by domain wall pinning, defect agglomeration, or other effects, will be critical to deliver commercially viable applications. Theoretical and experimental evidence [38,39,88,89] have provided great mechanistic insights into the physics of fatigue, but improved theories and models are required to optimize the microstructure and performance of materials.…”