First-principle calculation and assignment for vibrational spectra of Ba(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} microwave dielectric ceramic
- College of Physics and Electronics, Shandong Normal University, Jinan 250014 (China)
- State Key Laboratory for Artificial Microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871 (China)
- State Key Laboratory of Rare Earth Materials Chemistry and Applications, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871 (China)
- National Synchrotron Radiation Laboratory, University of Science and Technology of China, Hefei 230029 (China)
- MOE Key Laboratory of New Processing Technology for Nonferrous Metals and Materials, College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004 (China)
1:2 B-site cation ordered Ba(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} ceramic was synthesized using conventional solid-state reaction at 1600 °C for 12 h. The structure parameters were obtained through Rietveld refinement of X-ray diffraction data. The Raman peak frequencies were obtained by Lorenz fitting on Raman spectrum. Four-parameter semiquantum model was used to fit the infrared (IR) reflectivity spectrum, and the fitted parameters were used to calculate the dielectric permittivity ε and dielectric loss tanδ. A total of 9 active Raman and 16 active IR modes were obtained using first-principle calculations based on density functional theory with local density approximation. All of the vibrational modes were assigned and represented by linear combinations of the symmetry coordinates deduced using group theory analysis. The Raman mode with the highest frequency A{sub 1g}{sup (4)} (789 cm{sup −1}) can be described as the breathing vibration of NbO{sub 6}. The IR modes E{sub u}{sup (1)} (149 cm{sup −1}) and A{sub 2u}{sup (2)} (212 cm{sup −1}), which can be described as the twisting vibrations of Ba–MgO{sub 6}/Ba–NbO{sub 6} on the a–b plane and the stretching vibrations of Ba–MgO{sub 6}/Ba–NbO{sub 6} along the c direction, respectively, are the dominant contributing modes to ε and tanδ. The dielectric property parameters obtained using IR spectrum fittings, first-principal calculations, and microwave measurements were compared.
- OSTI ID:
- 22271322
- Journal Information:
- Journal of Applied Physics, Vol. 115, Issue 11; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
APPROXIMATIONS
BARIUM OXIDES
CATIONS
CERAMICS
COMPARATIVE EVALUATIONS
DENSITY FUNCTIONAL METHOD
DIELECTRIC MATERIALS
GROUP THEORY
INFRARED SPECTRA
MAGNESIUM OXIDES
MICROWAVE RADIATION
NIOBIUM OXIDES
PERMITTIVITY
RAMAN SPECTRA
REFLECTIVITY
SOLIDS
X-RAY DIFFRACTION