Enhanced optical and dielectric properties of rare-earth co-doped SrTiO3 ceramics

• Published in: Journal of materials science. Materials in electronics Vol. 32; no. 10; pp. 13837 - 13849
• Main Authors: Pradhan, Jagabandhu, Mallick, H. K., Sahoo, M. P. K., Pattanaik, A. K.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-05-2021; Springer Nature B.V
• Subjects: Ball milling; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Dielectric loss; Dielectric properties; Dipoles; Doping; Gadolinium; Grain boundaries; Materials Science; Optical and Electronic Materials; Optical properties; Perovskite structure; Perovskites; Rare earth elements; Strontium titanates
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-021-05959-7

Segregation of secondary phases at the grain boundary plays a vital role in increasing the value of dielectric constant and decreasing dielectric loss in dielectric materials. Herein, La/Gd co-doped SrTiO
3
(STO) ceramics of compositions La
0.1
Sr
0.9−
x
Gd
x
TiO
3
(
x
 = 0.05, 0.07, 0.09, 0.11), henceforth abbreviated as LGST, have been prepared in conventional solid-state route using a high energy ball mill. The X-ray diffraction technique (XRD) and scanning electron microscopy (SEM) were used to investigate structural and microstructural structures, respectively. The dielectric and electrical parameters are studied in a frequency ranging from 1 kHz to 1 MHz within the temperature ranging from 30 to 450 °C. The results demonstrate that all the synthesized samples exhibit single-phase perovskite structure with
P
m
3
¯
m
space group. The prepared LGST samples exhibit increasing dielectric maximum (
ε
r
 = 18,218) with the increase in the doping concentration. The enhanced dielectric behavior in the doped samples is attributed to the segregation of the secondary phase followed by localized transport mediated by defect dipole and defect clusters. Nevertheless, La/Gd co-doping results in a systematic reduction in the band gap from 3.19 to 3.13 eV of STO.