Domain engineering via liquid nitrogen quenching in bismuth sodium titanate-based relaxor-ferroelectric thin films
Journal
Ceramics International
ISSN
0272-8842
Date Issued
2025-01
Author(s)
Ting-Yu Chen
Abstract
A comparison study of air cooling (AC) and liquid nitrogen quenching (LNQ) on the ferroelectric, domain, and energy storage properties of 3 mol% Mn-doped 0.8(Bi0.5Na0.5)TiO3–0.2(Bi0.5K0.5)TiO3 thin films prepared via the sol-gel method was performed. LNQ treatment resulted in softer ferroelectricity with larger remanent polarization (Pr) and maximum polarization (Pmax) compared to AC treatment. Specifically, LNQ increased the film's recoverable energy storage density (Wrec) by nearly 23% at 680 kV/cm, from 8.2 to 10.1 J/cm3, although efficiency (η) dropped to 57.4% due to increased Pr. Regardless of the cooling method, additional nitrogen (N2) passivation annealing at 750 °C slimmed down the film's polarization hysteresis and improved energy storage performance by reducing leakage and internal field. With LNQ followed by N2 annealing, the film's Wrec and η reached close to 12.0 J/cm3 and 70% at 680 kV/cm, respectively. High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) analysis of the film revealed a predominantly pseudo-cubic structure. Through cation displacement, dipole moment, and c/a ratio mapping of the HAADF images, it has been shown that LNQ treatment induced larger lattice distortion with numerous small domains (< 5 nm) forming non-180° domain walls. Such a domain arrangement had a smaller onset of switching and would facilitate polarization reversal during electric field cycling, producing a soft polarization hysteresis with larger Pr, Pmax, and permittivity.
Subjects
Bismuth sodium titanate
Domain engineering
Energy storage
HAADF-STEM
Liquid nitrogen quenching
Nitrogen passivation
SDGs
Publisher
Elsevier BV
Type
journal article