BaMoO_(4)ceramic was prepared using a conventional solid-sintering method.It was observed that the sample is a pure BaMoO_(4)with a tetragonal scheelite structure by analyzing X-ray diffraction data.Scanning electron ...BaMoO_(4)ceramic was prepared using a conventional solid-sintering method.It was observed that the sample is a pure BaMoO_(4)with a tetragonal scheelite structure by analyzing X-ray diffraction data.Scanning electron microscopy characterized the dense sample with uniform grains.The phonon modes were analyzed by Raman and Far-infrared reflection spectra,and the phonon characteristics were studied.The intrinsic properties of the sample were calculated by the four-parameter semi-quantum model as well as the Clausius-Mosotti&damping equations,and the results were ofεr=9.388 and tanδ=4.760×10^(-4),εr=9.798 and tanδ=6.445×10^(-4),respectively,which agrees well with the experimental values(εr=9.84,tanδ=5.0×10^(-4)).The contributions to dielectric properties of each mode were investigated,and the results indicate that the external mode(Eu)yield greatest contribution to intrinsic permittivity and loss.展开更多
La(Mg_(1/2)Sn_(1/2))O_(3)(LMS)ceramic was synthesized via the conventional solid-state reaction method.The main phase of the sample is LMS with a double perovskite structure(monoclinic P121/n1 symmetry),which is confi...La(Mg_(1/2)Sn_(1/2))O_(3)(LMS)ceramic was synthesized via the conventional solid-state reaction method.The main phase of the sample is LMS with a double perovskite structure(monoclinic P121/n1 symmetry),which is confirmed by X-ray diffraction.Scanning electron microscopy shows the sample is wellcrystallized with dense and uniform grains as well as clear grain boundaries.The Raman scattering and Fourier transform far-infrared reflection spectroscopies were employed to analyze the lattice vibrational modes of the sample.The Raman active modes were fitted by the Lorentz function,and the lattice vibrational modes were assigned and illustrated accurately.The four-parameter semiquantum model was applied to simulate the intrinsic dielectric properties,which agree well with the data calculated from the microscopic polarizability&damping angles.The A1g(La)Raman mode in A-site has a great impact on the dielectric loss,and F^(2)_(3u)mode makes the largest contribution to the dielectric constant and the dielectric loss.展开更多
基金National Natural Science Foundation of China(Grant 11874240)the Taishan Scholarship Project of Shandong Province,China(No.tshw20130956)+3 种基金the Natural Science Foundation of Shandong Province,China(No.ZR2016EMM21)Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents(No.2016RCJJ002)the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure(No.SKL201503SIC)the State Key Laboratory of New Ceramic and Fine Processing Tsinghua University(No.KF201811).
文摘BaMoO_(4)ceramic was prepared using a conventional solid-sintering method.It was observed that the sample is a pure BaMoO_(4)with a tetragonal scheelite structure by analyzing X-ray diffraction data.Scanning electron microscopy characterized the dense sample with uniform grains.The phonon modes were analyzed by Raman and Far-infrared reflection spectra,and the phonon characteristics were studied.The intrinsic properties of the sample were calculated by the four-parameter semi-quantum model as well as the Clausius-Mosotti&damping equations,and the results were ofεr=9.388 and tanδ=4.760×10^(-4),εr=9.798 and tanδ=6.445×10^(-4),respectively,which agrees well with the experimental values(εr=9.84,tanδ=5.0×10^(-4)).The contributions to dielectric properties of each mode were investigated,and the results indicate that the external mode(Eu)yield greatest contribution to intrinsic permittivity and loss.
基金the National Natural Science Foundation of China(Grant No.61501409)Natural Science Foundation of Shandong Province,China(Grant No.ZR2016EMM21)+1 种基金Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents(Grant No.2016RCJJ002)the Opening Project of State Key Laboratory of High Performance Ceramics and Superfine Microstructure(Grant No.SKL201503SIC).
文摘La(Mg_(1/2)Sn_(1/2))O_(3)(LMS)ceramic was synthesized via the conventional solid-state reaction method.The main phase of the sample is LMS with a double perovskite structure(monoclinic P121/n1 symmetry),which is confirmed by X-ray diffraction.Scanning electron microscopy shows the sample is wellcrystallized with dense and uniform grains as well as clear grain boundaries.The Raman scattering and Fourier transform far-infrared reflection spectroscopies were employed to analyze the lattice vibrational modes of the sample.The Raman active modes were fitted by the Lorentz function,and the lattice vibrational modes were assigned and illustrated accurately.The four-parameter semiquantum model was applied to simulate the intrinsic dielectric properties,which agree well with the data calculated from the microscopic polarizability&damping angles.The A1g(La)Raman mode in A-site has a great impact on the dielectric loss,and F^(2)_(3u)mode makes the largest contribution to the dielectric constant and the dielectric loss.
