Effects of Er³⁺ and Pr³⁺ Substitution on Structural, Dielectric, Ferroelectric and Photoluminescence Properties of the BaTi_0.9Zr_0.1O₃ Ceramic

Abstract

BaTi_0.9Zr_0.1O₃ (BZT), Ba_1−x Ln_2x/3□ _x/3Ti_0.9Zr_0.1O₃ (with x = 0.5% mol and Ln = Er³⁺) (BZT-Er) and Ba_1−x Ln_2x/3□ _x/3Ti_0.9Zr_0.1O₃ (with x = 0.5% mol and Ln = Pr³⁺) (BZT-Pr) were prepared via the conventional solid-state reaction method. X-ray diffraction showed that all these ceramics were in the single perovskite phase at room temperature (RT). The temperature dependence of dielectric behavior was investigated in the temperature range 25–225°C and exhibited a classical ferroelectric behavior. A slight decrease of the Curie temperature (T _C) with Pr³⁺ and Er³⁺ substitution was observed in addition to an increase in the maximum dielectric permittivity ($\varepsilon_{r\,\rm{max} }^{{\prime }}$) of about 40% for the BZT-Er. At RT, the ferroelectric and piezoelectric coefficients were decreased for BZT-Pr, but were maintained for BZT-Er with a piezoelectric coefficient (d ₃₃) of 185 pC/N, a planar electromechanical coupling factor of 30%, and a remanent polarization of 11.6 μC/cm². The Raman bands as a function of temperature confirmed the paraelectric-ferroelectric phase transition of all those ceramics. The photoluminescence spectra showed that strong red (615 nm and 645 nm) and bright green (523 nm and 545 nm) emission bands were obtained, under excitation by laser at 488 nm at RT, for BZT-Pr and BZT-Er, respectively. These multifunctional materials showed a significant technological promise in coupling device applications.