Enhanced Ferroelectric and Dielectric Properties of Niobium-Doped Lead-Free Piezoceramics

Faysal Naeem; Mohsin Saleem; Hamid Jabbar; Gulraiz Tanvir; Fiza Asif; Abrar H Baluch; Muhammad Irfan; Abdul Ghaffar; Adnan Maqbool; Tayyab Rafiq

doi:10.3390/ma16020477

Enhanced Ferroelectric and Dielectric Properties of Niobium-Doped Lead-Free Piezoceramics

Materials (Basel). 2023 Jan 4;16(2):477. doi: 10.3390/ma16020477.

Authors

Faysal Naeem¹, Mohsin Saleem^{1

2}, Hamid Jabbar³, Gulraiz Tanvir¹, Fiza Asif¹, Abrar H Baluch⁴, Muhammad Irfan^{1

2}, Abdul Ghaffar⁵, Adnan Maqbool⁶, Tayyab Rafiq¹

Affiliations

¹ School of Chemical and Materials Engineering (SCME), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan.
² School of Interdisciplinary Engineering & Sciences, National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan.
³ Department of Mechatronics Engineering, College of Electrical and Mechanical Engineering (CEME), National University of Sciences and Technology (NUST), Islamabad 44000, Pakistan.
⁴ Department of Material Science & Engineering, Institute of Space Technology, Islamabad 44000, Pakistan.
⁵ Department of Physics, Government College University, Lahore 54000, Pakistan.
⁶ Department of Metallurgical & Materials Engineering, University of Engineering & Technology (UET), Lahore 54890, Pakistan.

Abstract

Lead-free ceramics are promising candidates for replacing lead-based piezoelectric materials such as lead-zirconate-titanate (PZT) if they can compete in dielectric and ferroelectric characteristics. In this work, for lead-free piezoelectric ceramic, 0.74(Bi_0.5Na_0.5TiO₃)-0.26(SrTiO₃) (BNT-ST26) and niobium-substituted (Nb-BNT-ST26) ceramics were synthesized by solid-state reactions. The evolution of niobium substitution to the perovskite phase structure of BNT-ST26 ceramics was confirmed by X-ray diffraction (XRD) analysis and Raman spectra. Electromechanical properties of Nb-BNT-ST26 ceramics initially increased with the addition of niobium up to 0.5% and decreased with a further increase in Nb content. Temperature-dependent dielectric curves showed that the depolarization temperature (T_d) decreased below room temperature because of Nb substitution. The composition with 0.5% Nb yielded a maximum bipolar strain (S_max) of 0.265% and normalized strain of d₃₃* ~ 576 pm/V under an electric field of 4.6 kV/mm at room temperature. At this critical concentration of 0.5% Nb, maximum saturation polarization of 26 μC/cm² was achieved. The dielectric constant with temperature peaks became more diffused and the depolarization temperature decreased with the increasing Nb content. The study concludes that Nb-doped BNT-ST26 is an excellent material for high-temperature, stable, frequency-dependent, lead-free piezoelectric devices.

Keywords: dielectric; dopant; ferroelectric; materials; piezoelectric.

Grants and funding

This work was funded by Pakistan’s National Center of Robotics and Automation (NCRA) research fund “Indigenous Approach for Development of Piezoelectric Devices” (RF-NCRA-035), 2020.