Journal
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
Volume 41, Issue 16, Pages 158-164Publisher
ELSEVIER SCI LTD
DOI: 10.1016/j.jeurceramsoc.2021.09.016
Keywords
Hexagonal perovskite; Thermally-stimulated relaxations; Defects; Microwave dielectrics; Terahertz properties
Categories
Funding
- National Key Research and Devel-opment Program of China [2017YFB0406301]
- Key-Area Research and Development Program of Guangdong Province [2020B010176001]
- National Natural Science Foundation of China [51872160]
Ask authors/readers for more resources
This study systematically investigated the thermally-stimulated relaxation of defects in La,Al co-substituted (Ba,Sr)La4Ti4O15 dielectric ceramics with a hexagonal perovskite structure. The ion substitution decreased lattice parameters and bond lengths, leading to a decrease in the concentration of oxygen vacancies and damping factor of lattice vibration, ultimately reducing microwave/terahertz dielectric loss. High-performance ceramics with specific properties were obtained, and the correlations between crystal structures, defect behaviors, and dielectric properties discussed in this work could guide the modification of microwave dielectric ceramics.
The thermally-stimulated relaxation of defects in La,Al co-substituted (Ba,Sr)La4Ti4O15 dielectric ceramics with hexagonal perovskite structure were investigated systematically with the thermally stimulated depolarization current (TSDC) measurements. The ion substitution decreased the lattice parameters and the bond lengths of the cations and O2-. TSDC spectra indicated the main extrinsic defects in the ceramics were oxygen vacancies and the concentration of oxygen vacancies decreased with the increasing ion substitutions, which was derived from the decrease in the lattice parameters. The terahertz time-domain spectra indicated the damping factor of lattice vibration was reduced with the decline of the concentration of oxygen vacancies, which decreased the microwave/terahertz dielectric loss. High-performance (Ba0.2Sr0.8)(0.75)La4.25Ti3.75Al0.25O15 (er = 43.9, Q x f = 84300 GHz, if =-18.0 ppm/degrees C) ceramics were obtained. The correlations between crystal structures, defect behaviors and dielectric properties discussed in this work could provide guidance for the modification of microwave dielectric ceramics.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available