Influences of Sr2+ Doping on Microstructure, Giant Dielectric Behavior, and Non-Ohmic Properties of CaCu3Ti4O12/CaTiO3 Ceramic Composites

Jutapol Jumpatam; Bundit Putasaeng; Narong Chanlek; Prasit Thongbai

doi:10.3390/molecules26071994

Influences of Sr²⁺ Doping on Microstructure, Giant Dielectric Behavior, and Non-Ohmic Properties of CaCu₃Ti₄O₁₂/CaTiO₃ Ceramic Composites

Molecules. 2021 Apr 1;26(7):1994. doi: 10.3390/molecules26071994.

Authors

Jutapol Jumpatam¹, Bundit Putasaeng², Narong Chanlek³, Prasit Thongbai^{4

5}

Affiliations

¹ Department of Fundamental Science, Faculty of Science and Technology, Surindra Rajabhat University, Surin 32000, Thailand.
² National Metal and Materials Technology Center (MTEC), Thailand Science Park, Pathumthani 12120, Thailand.
³ Synchrotron Light Research Institute (Public Organization), 111 University Avenue, Muang District, Nakhon Ratchasima 30000, Thailand.
⁴ Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand.
⁵ Institute of Nanomaterials Research and Innovation for Energy (IN-RIE), Khon Kaen University, Khon Kaen 40002, Thailand.

Abstract

The microstructure, dielectric response, and nonlinear current-voltage properties of Sr²⁺-doped CaCu₃Ti₄O₁₂/CaTiO₃ (CCTO/CTO) ceramic composites, which were prepared by a solid-state reaction method using a single step from the starting nominal composition of CCTO/CTO/xSrO, were investigated. The CCTO and CTO phases were detected in the X-ray diffraction patterns. The lattice parameter increased with increasing Sr²⁺ doping concentration. The phase compositions of CCTO and CTO were confirmed by energy-dispersive X-ray spectroscopy with elemental mapping in the sintered ceramics. It can be confirmed that most of the Sr²⁺ ions substituted into the CTO phase, while some minor portion substituted into the CCTO phase. Furthermore, small segregation of Cu-rich was observed along the grain boundaries. The dielectric permittivity of the CCTO/CTO composite slightly decreased by doping with Sr²⁺, while the loss tangent was greatly reduced. Furthermore, the dielectric properties in a high-temperature range of the Sr²⁺-doped CCTO/CTO ceramic composites can be improved. Interestingly, the nonlinear electrical properties of the Sr²⁺-doped CCTO/CTO ceramic composites were significantly enhanced. The improved dielectric and nonlinear electrical properties of the Sr²⁺-doped CCTO/CTO ceramic composites were explained by the enhancement of the electrical properties of the internal interfaces.

Keywords: CaCu3Ti4O12/CaTiO3; ceramic composite; dielectric permittivity; loss tangent; non-Ohmic properties.

Abstract

Grants and funding