Super Stable Ferroelectrics with High Curie Point

Ferroelectric materials are of great importance in the sensing technology due to the piezoelectric properties. Thermal depoling behavior of ferroelectrics determines the upper temperature limit of their application. So far, there is no piezoelectric material working above 800 degrees C available. Here, we show Nd2Ti2O7 with a perovskite-like layered structure has good resistance to thermal depoling up to 1400 degrees C. Its stable behavior is because the material has only 180 degrees ferroelectric domains, complex structure change at Curie point (T-c) and their sintering temperature is below their T-c, which avoided the internal stresses produced by the unit cell volume change at T-c. The phase transition at T-c shows a first order behavior which involving the tilting and rotation of the octahedron. The Curie - Weiss temperature is calculated, which might explain why the thermal depoling starts at about 1400 degrees C.