Phase Formation, Microstructure, Electric and Magnetic Properties of NiO Doping in (Ba_0.85Ca_0.15)(Ti_0.90Zr_0.10)O₃ Ceramics

Abstract

Lead-free (Ba_0.85Ca_0.15)(Ti_0.90Zr_0.10)O₃-xNiO (x = 0, 0.2, 0.4, 0.6 and 0.8 wt%) ceramics were prepared by the solid-state combustion technique using glycine as a fuel. The effect of NiO doping on the phase formation, microstructure, electrical and magnetic properties of the ceramics was investigated. The powders and ceramics were calcined and sintered at a temperature of 1050 °C and 1450 °C for 2 h, respectively. XRD results showed that all ceramics had coexisting orthorhombic and tetragonal phases. Increasing the amount of NiO doping enhanced the amount of tetragonal phase, as verified by the Rietveld refinement technique. The density values (ρ) and the average grain size rapidly decreased from 5.79 to 4.69 g/cm³ and 37.8 ± 3.6 to 3.0 ± 0.3 µm when NiO doping increased from 0 to 0.8 wt%. The values of the dielectric constant (ε), dielectric loss (tan δ) and remnant polarization (P_r) tended to decrease when NiO doping increased. Only the sample with 0.4 wt% NiO exhibited ferromagnetic behavior at room temperature, with a remnant magnetization (M_r) and a coercive field (H_c) of 1.04 × 10⁻⁵emu/g and 72.55 Oe, respectively.

Keywords:

• BCTZ-xNiO
• phase formation
• dielectric properties
• magnetic properties
• solid state combustion technique

Acknowledgment

The authors wish to thank the Department of Physics, Faculty of Science, Naresuan University for their supporting facilities. Thanks are also given to Asst. Prof. Dr. Kyle V. Lopin for his help in editing the manuscript.

Additional information

Funding

This work was supported by the Faculty of Science, Naresuan University and the National Science, Research and Innovation Fund (NSRF).