The Phase Structure, Microstructure, Dielectric and Magnetic Properties of 0.99(K_0.45Na_0.52Li_0.03)(Nb_0.94Sb_0.06)O₃-0.01BiScO₃ Ceramics with NiO Doping

Abstract

The effect of NiO doping (0–0.8 wt%) on the phase structure, microstructure, dielectric and magnetic properties of 0.99(K_0.45Na_0.52Li_0.03)(Nb_0.94Sb_0.06)O₃-0.01BiScO₃ (KNLNS-BS) ceramics was investigated. The samples were fabricated by the solid-state combustion technique with glycine used as fuel. Powders and ceramics were calcined and sintered at temperatures of 700 °C for 1 h and 1120 °C for 3 h, respectively. The phase formation from the XRD results showed a pure perovskite structure with coexisting rhombohedral and tetragonal phases in all samples. The ratio of the rhombohedral and tetragonal phases (R:T) of the 0.6 wt% NiO doped sample was 40:60, as verified by the Rietveld refinement technique. The grain morphology of the ceramics exhibited irregular polyhedron shapes and the average grain size was in the range of 1.3 ± 0.15 to 2.6 ± 0.51 µm. KNLNS-BS ceramics with 0.6 wt% added NiO had the highest density (4.40 g/cm³) and the highest maximum dielectric constant (ε_C = 5013). Without NiO doping, the ceramic showed diamagnetic behavior, whereas all of the NiO-doped ceramics exhibited paramagnetic behavior measured at a temperature of 50 K.

Keywords:

• Phase structure
• microstructure
• dielectric properties
• magnetic properties
• solid state combustion technique

Acknowledgments

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