123rd General Meeting of the KCS

Type Oral Presentation
Area Oral Presentation of Young Material Chemists
Room No. Room 405+406
Time THU 09:36-09:48
Code MAT.O-4
Subject Microwave absorption enhancement via BaTiO3 particles with oxygen vacancies.
Authors Jerome Hyun*, Baek Kyungnae1
Chemistry Department of Nano-Science, Ewha Womans University, Korea
1Department of Chemistry, Ewha Womans University, Korea
Abstract Microwave absorption is important for preventing electronic malfunction in electronic devices due to electromagnetic interference. Microwave absorbing materials with high magnetic permeability or high dielectric loss are typically employed. BaTiO3 is a ferroelectric material and can be applied as efficient microwave absorbers. The movement of the domain wall affects the dielectric properties of many ferroelectric materials in the microwave range. Microwave absorption of the ferroelectric material can be enhanced by controlling the movement of the domain wall. In this study, we used the coupling of oxygen vacancy to control the domain wall motion, thereby exploring the improvement of microwave absorption in ferroelectric BaTiO3 particles. BaTiO3-x particles were prepared by the Molten Salt Synthesis (MSS) method. Oxygen vacancies were introduced through synthesis in an oxygen deficient environment. The presence, relative concentration and predominant type of oxygen vacancies were confirmed using Raman, electron paramagnetic resonance (EPR) and Electron energy loss spectroscopy (EELS) analysis. We found that increased oxygen vacancy content by 15-folds enhanced the microwave absorption in BaTiO3-x particles by 26.3dB. The calculated reflection loss value of oxygen deficient BaTiO3-x particles was enhanced up to -43dB at 5GHz. From a Debye relaxation model, we attributed the increase in microwave absorption to the slowing of domain wall movement by oxygen vacancies. These results demonstrate effective control over microwave absorption using facile and cheap incorporation of oxygen vacancies in dielectric fillers. [1] K. Baek et al., “Axial oxygen-vacancy-regulated microwave absorption in micron-sized tetragonal BaTiO3 particles” J. Mater. Chem. C, 2018, 6, 9749-9755
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