Study of Bi<inf>0.5</inf>NA<inf>0.5</inf>TiO<inf>3</inf> system doped with La³⁺ obtained by acetic acid route in sol-gel process

Abstract:

This work studies the system Bi0.5NA0.5TiO3 (BNT) doped with lanthanum (La3+) at molar concentrations 0.0, 0.3, 0.6, 0.8, 1.0, 3.0 and 6.0. The samples were synthesized by the Sol-gel method using the acetic acid route. The bulk samples were calcined at 700 ºC/1hr in order to obtain the perovskite phase, and finally the samples were sintered at 1050 ºC/1hr, obtaining density values between 90 and 92% with respect to the theoretical density. The La doping effect in the BNT system was analyzed using X-ray diffraction (DRX), Scanning electron microscopy (SEM), Ferroelectric hysteresis curves and Raman spectroscopy. The samples show a crystalline rhombohedral structure and is observed a decreasing behavior of the grain size for La concentrations greater than 0.3%. After the incorporation of 0.6% lanthanum concentration, the presence of the pyrochlore phase of Bi2Ti2O7 is observed. The best ferroelectric properties were obtained for BNT doped with lanthanum (La3+) at 6% in which a rhombohedral structure and traces of pyrochlore phases were obtained. This sample presented maximum polarization (Pm) of 22.55 µC/cm2, remnant polarization (Pr) of 22.06 µC/cm2 and a coercive field (Ec) of 25 kV/cm.

Año de publicación:

2020

Keywords:

• Ferroelectric ceramics
• Multifunctional materials
• BNT
• Piezoelectrics

Fuente:

scopus