Behaviour of Ferroelastic and Ferroelectric Domains in AgNbO₃ Under Temperature and Stress Influence

By deploying different modes of atomic force microscopy, both ferroelectric and ferroelastic domains with distinct morphology and orientations are observed in the well-known antiferroelectric AgNbO₃, consistent with the theoretical studies. With temperature, ferroelectric domains disappear across its M₁-M₂ phase boundary when it becomes antiferroelectric. In contrast, ferroelastic domains remain stable at 100 °C, consistent with the fact that the ferroelasticity persists till high-temperature antiferroelectric phase regions. In addition, it is found that the number of ferroelectric domains inside the sample is related to the level of Ag deficiency. With applying compressive stress, the ferroelectric surface domains would gradually respond to the stress, which either grows, shrinks or changes shape. In comparison, the ferroelastic surface domains seem to show better mechanical resistance and did not respond as much as the ferroelectric domains.