Effects of Sintering Conditions on Giant Dielectric and Nonlinear Current–Voltage Properties of TiO<sub>2</sub>-Excessive Na<sub>1/2</sub>Y<sub>1/2</sub>Cu<sub>3</sub>Ti<sub>4.1</sub>O<sub>12</sub> Ceramics
Pariwat Saengvong,
Jakkree Boonlakhorn,
Narong Chanlek,
Nutthakritta Phromviyo,
Viyada Harnchana,
Pairot Moontragoon,
Pornjuk Srepusharawoot,
Sriprajak Krongsuk,
Prasit Thongbai
Affiliations
Pariwat Saengvong
Giant Dielectric and Computational Design Research Group (GD–CDR), Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
Jakkree Boonlakhorn
Department of Basic Science and Mathematics, Faculty of Science, Thaksin University, Songkhla 90000, Thailand
Narong Chanlek
Synchrotron Light Research Institute (Public Organization), 111 University Avenue, Muang District, Nakhon Ratchasima 30000, Thailand
Nutthakritta Phromviyo
Giant Dielectric and Computational Design Research Group (GD–CDR), Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
Viyada Harnchana
Giant Dielectric and Computational Design Research Group (GD–CDR), Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
Pairot Moontragoon
Giant Dielectric and Computational Design Research Group (GD–CDR), Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
Pornjuk Srepusharawoot
Giant Dielectric and Computational Design Research Group (GD–CDR), Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
Sriprajak Krongsuk
Giant Dielectric and Computational Design Research Group (GD–CDR), Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
Prasit Thongbai
Giant Dielectric and Computational Design Research Group (GD–CDR), Department of Physics, Faculty of Science, Khon Kaen University, Khon Kaen 40002, Thailand
The effects of the sintering conditions on the phase compositions, microstructure, electrical properties, and dielectric responses of TiO2-excessive Na1/2Y1/2Cu3Ti4.1O12 ceramics prepared by a solid-state reaction method were investigated. A pure phase of the Na1/2Y1/2Cu3Ti4.1O12 ceramic was achieved in all sintered ceramics. The mean grain size slightly increased with increasing sintering time (from 1 to 15 h after sintering at 1070 °C) and sintering temperature from 1070 to 1090 °C for 5 h. The primary elements were dispersed in the microstructure. Low dielectric loss tangents (tan δ~0.018–0.022) were obtained. Moreover, the dielectric constant increased from ε′~5396 to 25,565 upon changing the sintering conditions. The lowest tan δ of 0.009 at 1 kHz was obtained. The electrical responses of the semiconducting grain and insulating grain boundary were studied using impedance and admittance spectroscopies. The breakdown voltage and nonlinear coefficient decreased significantly as the sintering temperature and time increased. The presence of Cu+, Cu3+, and Ti3+ was examined using X-ray photoelectron spectroscopy, confirming the formation of semiconducting grains. The dielectric and electrical properties were described using Maxwell–Wagner relaxation, based on the internal barrier layer capacitor model.
