A sodium bismuth titanate-based material with both high depolarization temperature and large pyroelectric response

Abstract

Practical pyroelectric materials require excellent pyroelectric performance, high depolarization temperature, and good temperature stability. In this work, the microstructure, ferroelectric, dielectric, and pyroelectric properties were studied systematically in (Bi0.5Na0.5)TiO3–0.1%MnCO3 (BNT–Mn) lead-free ceramics. It is observed that the pyroelectric coefficient p reaches 2.90 × 10−4 C m−2 K−1 at room temperature in the samples. Due to the low dielectric constant (291) and dielectric loss (0.010), the figures of merit (FoMs) Fi, Fv, and FD are as high as 1.03 × 10−10 m/V, 4.05 × 10−2 m2/C, and 1.86 × 10−5 Pa−1/2, measured at 1 kHz. With the increase in temperature, the p and FoMs change slightly, showing good temperature stability. More importantly, a relatively high depolarization temperature of 205 °C is achieved, which should help deliver reliable operation in practice. In general, all performances reveal that BNT–Mn ceramics are expected to pave the way for uncooled infrared detector applications.