Enhanced piezoelectric and pyroelectric effects in single-phase multiferroic Bi[sub 1−x]Nd[sub x]FeO₃ (x = 0–0.15)

Abstract

Single-phase multiferroic Bi[sub1−x]Nd[subx]FeO₃ (x = 0–0.15) ceramics are polarized and their piezoelectric and pyroelectric effects are reported. The success in polarizing the ceramics originates from low electrical conductivities controlled predominantly by the Poole-Frenkel conduction mechanism. Limited internal traps due to reduced oxygen vacancies in the ceramics result in sufficiently low leakage current densities of <30 mA/m² even at a high electric field of 145 kV/cm. The piezoelectric d₃₃ coefficients of the ceramics before and after annealing at 550 °C for 4 h are measured to be ∼ 28 and ∼ 24 pC/N, respectively. These values are higher than those of most major lead-free high-temperature piezoelectric ceramics.