Reversible evolution of ferroelectric-antiferroelectric phase transition in lanthanum-modified NaNbO3-based ceramics

• Published in: Journal of the European Ceramic Society Vol. 44; no. 1; pp. 233 - 241
• Main Authors: Tao, Hong, Yin, Jie, Zhao, Chunlin, Zhao, Lin, Wu, Bo, Ma, Jian, Ergu, Daji
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-01-2024
• Subjects: Ferroelectric-antiferroelectric phase transition; Ions substitution; Sodium niobate ceramics; Ferroelectric-antiferroelectric phase transition; Sodium niobate ceramics; Ions substitution
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2023.09.020

Sodium niobate (NN) lead-free perovskites have been concentrated on due to high performance and abundant phase structure. The complex structure evolution has become a hot topic of research for this kind of materials. In this work, antiferroelectric phase is recovered by introducing La3+ dopant from modified ferroelectric states, indicating reversible composition-induced antiferroelectric-ferroelectric (AFE-FE) phase transition in NN-based ceramics. Significantly, change tendency of decreasing first and then increasing appears for phase transition temperature with increasing La3+, which is different from general phenomenon for ions dopant. Antiferroelectric orthorhombic (Pbma) is induced from ferroelectric tetragonal (P4mm) with a transient state of paraelectric cubic (Pm3m) via enhancing La3+. Further, substitution on A-site and A/B-sites are revealed with low and high content of La3+, respectively, accompanied by decreased first and then increased oxygen vacancy. Moreover, obviously deteriorated piezoelectric response is observed along with poor domain switching due to the vanishing ferroelectric domain for FE-PE-AFE phase transition. Meanwhile, weak strain, piezoelectric and dielectric properties are observed for antiferroelectric phase with antiparallel dipoles, while enhanced strain and dielectric permittivity are gained around ferroelectric-paraelectric coexistence or paraelectric region originating from electric field-induced ferroelectric state from polar nanoregions. Thus, this work demonstrated an abnormal phase transition in NN-based ceramics, promoting the understanding of antiferroelectrics.