Sintering Temperature, Frequency, and Temperature Dependent Dielectric Properties of Na0.5Sm0.5Cu3Ti4O12 Ceramics

• Published in: Materials Vol. 14; no. 17; p. 4805
• Main Authors: Kotb, Hicham Mahfoz, Khater, Hassan A., Saber, Osama, Ahmad, Mohamad M.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 25.08.2021; MDPI
• Subjects: Activated sintering; Ceramics; Crystallites; Dielectric loss; Dielectric properties; Grain size; impedance spectroscopy; Investigations; Lattice strain; Lattice vacancies; Mathematical analysis; Morphology; Permittivity; Plasma sintering; Radiation; sintering; Sintering (powder metallurgy); Spectrum analysis; Temperature; Temperature dependence
• ISSN: 1996-1944; 1996-1944
• DOI: 10.3390/ma14174805

NSCTO (Na0.5Sm0.5Cu3Ti4O12) ceramics have been prepared by reactive sintering solid-state reaction where the powder was prepared from the elemental oxides by mechanochemical milling followed by conventional sintering in the temperature range 1000–1100 °C. The influence of sintering temperature on the structural and dielectric properties was thoroughly studied. X-ray diffraction analysis (XRD) revealed the formation of the cubic NSCTO phase. By using the Williamson–Hall approach, the crystallite size and lattice strain were calculated. Scanning electron microscope (SEM) observations revealed that the grain size of NSCTO ceramics is slightly dependent on the sintering temperature where the average grain size increased from 1.91 ± 0.36 μm to 2.58 ± 0.89 μm with increasing sintering temperature from 1000 °C to 1100 °C. The ceramic sample sintered at 1025 °C showed the best compromise between colossal relative permittivity (ε′ = 1.34 × 103) and low dielectric loss (tanδ = 0.043) values at 1.1 kHz and 300 K. The calculated activation energy for relaxation and conduction of NSCTO highlighted the important role of single and double ionized oxygen vacancies in these processes.