Structure and piezoelectric properties of BiFeO3 and Bi0.92Dy0.08FeO3 multiferroics at high temperature

► Piezoelectric responses were observed at 20-500 °C. ► Ferroelectric component existed at 650 °C in Bi0.92Dy0.08FeO3. ► The impedance and the resistance were below 10,000 Ω above 440 °C.