Novel, diverse and ultra-high ferroelectric, piezoelectric and dielectric performances of Mn added La2Ti2O7-based ceramics for high-temperature applications

Abstract

In the industry of high-temperature sensors and actuators, materials capable of delivering high ferroelectric, dielectric, and specifically stable/high piezoelectric performances above 1000 °C are in demand. Hence, perovskite-like layered structured (PLS) have gained popularity due to their high Curie temperature (T_C) and ferroelectric properties, but the low piezoelectric coefficient (d₃₃) at high temperature (>1000 °C) is the problem statement to be explored and improved. Herein this research, La_1.97(LiCe)_0.03Ti₂O₇:xwt%MnO₂ (LLCTO:xMn) with x = 0–0.3 ceramic series has been explored to study the ultra-high structural, ferroelectric, electric, dielectric, and piezoelectric properties. Among all compositions, LLCTO:0.2Mn ceramic has demonstrated ultra-high performances with remnant polarization (P_r) of ∼1.84 μC/cm², piezoelectric co-efficient (d₃₃) of 9 pC/N, resistivity of ∼10¹¹ Ω.cm, relative dielectric constant (ɛ_r) of 46, and minor dielectric loss (tanδ) of 0.17 which are much improved compared to pure La₂Ti₂O₇ (LTO) and pristine La_1.97(LiCe)_0.03Ti₂O₇ (LLCTO) ceramics. The LLCTO:0.2Mn ceramic has exhibited the high T_C of 1415 °C. Moreover, thermally stable multifunctional performances are measured where LLCTO:0.2Mn ceramic has demonstrated a high d₃₃ of ∼8.5 pC/N at 1200 °C and resistivity of ∼2.4 × 10⁷ Ω.cm even at 1000 °C, which are much better than the earlier reports. From the analysis, LLCTO:0.2Mn ceramic has demonstrated the potential to be utilized in high-temperature (>1000 °C) piezoelectric devices.