Thermally-induced loss of piezoelectricity in ferroelectric Na0.5Bi0.5TiO3–BaTiO3

Highlight
• Loss of piezoelectricity in ferroelectric (1−x)NBT−xBT with 0≤x≤13% was studied.
• Thermal depoling and Raman spectroscopy were the major techniques used.
• Highest thermal stability of piezoelectric coefficients is in x=13% d33 (118 pC/N).
• The morphotropic phase boundary composition (x=6%), exhibited the lowest Td.
• Raman spectra indicate a more disordered structure than unmodified NBT.

The loss of piezoelectricity in ferroelectric sodium bismuth titanate (NBT) in solid solution with barium titanate ((1−x)NBT−xBT) is studied by means of thermal depoling and Raman spectroscopy. In the range 0≤x≤13%, the highest thermal stability of the piezoelectric coefficients is found in x=13%, for which a longitudinal piezoelectric coefficient of 118 pC/N was nearly temperature-independent up to a maximum temperature of 165 °C. The composition nearest the morphotropic phase boundary, x=6%, exhibited the lowest thermal depoling temperature of 107 °C. Depoling of this composition is suggested to arise from a second order phase transition evidenced in the temperature-dependent Raman spectra.