# Effect of Ba:Ti Molar Ratio and Sintering Temperature on the Structural and Electrical Properties of BaTiO3-Type Solid Solutions, Synthesized by the Hydrothermal Method

## TL;DR

This paper studies how changing the Ba:Ti ratio and sintering temperature affects the structure and electrical properties of BaTiO3 ceramics made using the hydrothermal method.

## Contribution

The study provides new insights into optimizing BaTiO3 solid solutions by varying Ba:Ti molar ratios and sintering temperatures.

## Key findings

- A Ba:Ti ratio of 4:1 and sintering at 1300°C produced the highest relative permittivity values.
- The highest remnant polarization was observed for a Ba:Ti ratio of 4:1 and sintering at 1325°C.
- Grain size increased with higher sintering temperatures, as observed via HRSEM.

## Abstract

The results of the effect of the three Ba:Ti molar ratios (MR) (1:1, 2:1, 4:1) and four sintering temperatures (1250, 1275, 1300, 1325 °C) on the structural and electrical properties of BaTiO3 (BT)-type ceramics synthesized by the hydrothermal method are shown. The BT phase formed was analyzed by x-ray diffraction (XRD), Raman spectroscopy (RS), dielectric and ferroelectric measurements and high-resolution scanning electron microscopy (HRSEM). For the samples synthesized using a Ba:Ti MR of 4:1 and at all sintering temperatures analyzed, XRD results confirmed the presence of the tetragonal ferroelectric phase, BT. In the same way, these results corroborated the results obtained by the RS technique. Dielectric properties measured at 100 kHz and 1 MHz over a temperature range of 30 °C–200 °C indicated a relative permittivity value of 4280 at 1 MHz and 4200 at 100 KHz at a Curie temperature of 110 °C in both cases for the sample synthesized at with a Ba:Ti MR ratio of 4:1 and sintered at 1300 °C. Ferroelectric measurements for the samples showed a best remnant polarization (Pr) of 3.5 µC/cm2 for the sample synthesized with a Ba:Ti MR ratio of 4:1 and sintered at 1325 °C. The HRSEM results showed grains composed of Ba, Ti, and O homogeneously distributed in the BT structure, and a trend of increasing average grain size with increasing sintering temperature was observed.