Structure, ferroelectricity and piezoelectricity evolutions of Bi1−xSmxFeO3 at various temperatures

Insulated Bi1−xSmxFeO3 ( x = 0 – 0.25 ) were prepared to study their multiferroic properties at various temperatures. Bi1−xSmxFeO3 ( x = 0 − 0.12 ) shows a rhombohedral-like phase, ferroelectric polarization of >17.8 μC/cm2, piezoelectric d 33 value of >35 pC/N at room temperature. Bi1−xSmxFeO3 ( x = 0.125 – 0.2 ) has a ferroelectric triclinic phase and an anti-polar orthorhombic phase together at room temperature, and Bi0.75Sm0.25FeO3 is mainly composed of a non-polar orthorhombic phase. After the polarized Bi1−xSmxFeO3 ( x = 0 – 0.165 ) was annealed at various high temperatures, the d 33 evolution supports ferroelectric component exist above 500 °C. Raman spectra suggests that the main component of Bi0.875Sm0.125FeO3 does not keep a rhombohedral ferroelectric phase above 400 °C, thus its ferroelectric traits at high temperature should be due to ferroelectric clusters embedded in orthorhombic phase.