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

Insulated Bi1−xSmxFeO3 (x=0–0.25x=0–0.25) were prepared to study their multiferroic properties at various temperatures. Bi1−xSmxFeO3 (x=0−0.12x=0−0.12) shows a rhombohedral-like phase, ferroelectric polarization of >17.8 μC/cm2, piezoelectric d33d33 value of >35 pC/N at room temperature. Bi1−xSmxFeO3 (x=0.125–0.2x=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=0–0.165x=0–0.165) was annealed at various high temperatures, the d33d33 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.

► Bi1−xSmxFeO3 (x=0–0.12x=0–0.12) shows large polarization and d33d33 values.
► Ferroelectric clusters are embedded in Bi0.875Sm0.125FeO3 above 400 °C.
► Ferroelectric phase and anti-polar orthorhombic phase coexist at x=0.125–0.2x=0.125–0.2.