pISSN 0374-4914 eISSN 2289-0041

## Research Paper

New Phys.: Sae Mulli 2021; 71: 230-235

Published online March 31, 2021 https://doi.org/10.3938/NPSM.71.230

## BiFeO$_{3}$-BaTiO$_{3}$ Ceramics Modified by using BiAlO$_{3}$ with a high Curie Temperature and high Piezoelectric Coefficient

Hyung Rae CHO1, Myang Hwan LEE2, Da Jeong KIM1,2, Hae In CHOI2, Won-Jeong KIM3, Seong Su JEONG4, Tae Kwon SONG1,2*

1Department of Materials Convergence and System Engineering, Changwon National University, Changwon 51140, Korea

2School of Materials Science and Engineering, Changwon National University, Changwon 51140, Korea
3Department of Physics, Changwon National University, Changwon 51140, Korea
4Mechatronics Research Center, Changwon National University, Changwon 51140, Korea

Correspondence to:tksong@changwon.ac.kr

Received: January 8, 2021; Revised: February 5, 2021; Accepted: February 5, 2021

### Abstract

$[1-x]$Bi$_{1.03}$(Fe$_{0.99}$Al$_{0.01}$)O$_{3}$-$x$BaTiO$_{3}$ ($x$ = 0.30, 0.33, 0.35, and 0.40) lead-free piezoelectric ceramics were prepared through a conventional solid-state reaction method followed by a water-quenching process. A single perovskite structure without any impurity or secondary phase was confirmed for all compositions. The crystal phase, phase transition, microstructure, dielectric, ferroelectric, and piezoelectric properties were investigated. The temperature-dependent dielectric losses ($\tan \delta$) were found to decrease dramatically to 100 -- 200 $^{\circ}$C and then increased sharply at higher temperatures for $x$ = 0.30, 0.33, and 0.35. The ferroelectric properties improved with increasing measurement temperatures and the highest value of $2P_{r}$ = 80.2 $\upmu$C/cm$^{2}$ was observed at $x$ = 0.33 at 100 $^{\circ}$C. It was found that the best piezoelectric charge sensor coefficient ($d_{33}$) was 323 pC/N and the Curie temperature ($T_{C}$) was 452 $^{\circ}$C for $x$ = 0.33. The best piezoelectric actuator coefficient ($d_{33}^{*}$) was 515 pm/V and the $T_{C}$ was 344 $^{\circ}$C for $x$ = 0.40. These results showed that Al-doped BF-BT ceramics have great potential for were in high-temperature lead-free piezoelectric sensor and actuator applications.

Keywords: Lead-free, BiFeO$_{3}$, BaTiO$_{3}$, BiAlO$_{3}$, Ferroelectic