Aging effect and metastable ferroelectric state in Ba4Eu2(Ti0.9Zr0.1)4Ta6O30 tetragonal tungsten bronze ceramic.

The aging effect and the metastable ferroelectric state are investigated in the Ba4Eu2(Ti0.9Zr0.1)4Ta6O30 ceramic, where the tetragonal tungsten bronze structure with a P4bm space group is confirmed. When the compound is cooled from temperatures far above its transition temperature (TC), a very slim polarization-electric field curve is observed at 300 K. After 3 days of aging at 300 K, an obvious increase in the remanent polarization and the coercive electric field can be obtained. Moreover, a gradual recovery of the endothermic peak is detected in the differential scanning calorimeter curves when the compound is cooled from temperatures above TC and aged at 300 K for several days. These phenomena are interpreted as the result of a metastable ferroelectric state and the related aging effect, which may be deeply concerned with the compositional inhomogeneity and the hindered superstructure transformation. Through manipulating A and B site cation substitutions, the range of the metastable ferroelectric state can be tuned, and compounds with a different ferroelectric transition process can be obtained. [ABSTRACT FROM AUTHOR]