Colossal permittivity and ultralow dielectric loss in Nb-doped SrTiO3 ceramics

Abstract

Defect engineering has been applied to prepare materials with modifiable dielectric properties. SrTiNbxO3 (x = 0, 0.003, 0.006, 0.009, 0.012) ceramics were synthesized using the traditional solid-state reaction method and sintered in a reducing atmosphere. All samples show excellent dielectric properties with giant permittivity (> 3.5×104) and low dielectric loss (< 0.01). SrTiNb0.003O3 ceramic exhibits a colossal permittivity of 4.6×104 and an ultralow dielectric loss of 0.005 (1 kHz, room temperature) as well as great temperature stability in the range of (−60)–160℃. The mechanism of the presented colossal permittivity (CP) properties is investigated by conducting X-ray photoelectron spectroscopy (XPS) and analyzing activation energies. The results indicate that the introduction of Nb5+ and the reducing sintering atmosphere together generated the formation of Ti3+ and VO··. These defects further form TiTi′−VO··−TiTi′ defect dipoles, contributing to the coexisting giant permittivity and low dielectric loss in Nb-doped SrTiO3 (STN) ceramics.

Keywords

• srtio3
• colossal permittivity (cp)
• ultralow dielectric loss
• defect dipoles