Crystal structure, Raman spectroscopy, far-infrared, and microwave dielectric properties of (1-x)La(MgSn)0.5O3-xNd(MgSn)0.5O3 system
Crystal structure, Raman spectroscopy, far-infrared, and microwave dielectric properties of (1-x)La(MgSn)0.5O3-xNd(MgSn)0.5O3 system
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DOI：
10.1063/1.2902932
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发表时间：
2008-04-15
影响因子：
3.2
通讯作者：
Lobo, R. P. S. M.
中科院分区：
文献类型：
--
作者：
Babu, G. Santosh;Subramanian, V.;Lobo, R. P. S. M.
采用固相反应法制备了组成为（x=0-1）的（1-x）La(MgSn)(0.5)O-3- xnd (MgSn)(0.5)O-3复合钙钛矿体系。进行了结构和光谱研究，以了解介电性能随x的变化。利用结构预测和诊断软件获得的初始模型进行了Rietveld细化。结果表明，化合物的对称性为单斜斜，空间群为P2(1)/n，对应于a(-)a(-)c（+）倾斜体系，并且随着钕浓度的增加，远程序参数降低。通过拟合A（1g）类模来分析拉曼光谱的洛伦兹峰形。利用四参数半量子模型拟合红外反射光谱，估计了本征介电参数。计算了横向光学声子模强度和平均声子阻尼。讨论了本征损耗随成分变化而增大的原因。微波测量在9-11 GHz频率范围内进行。随着钕浓度的增加，介电常数减小，谐振频率温度系数减小。(c) 2008年美国物理研究所。
The complex perovskite system (1-x)La(MgSn)(0.5)O-3-xNd(MgSn)(0.5)O-3 with the composition (x=0-1) was prepared by the solid state reaction method. Structural and spectroscopic studies were carried out to understand the variation of dielectric properties with x. Rietveld refinement was carried out with the initial model obtained by using the structure prediction and diagnostic software. The symmetry of the compositions was determined to be monoclinic with space group P2(1)/n, which corresponds to the a(-)a(-)c(+) tilting system, and the long-range order parameter was found to decrease with an increase in neodymium concentration. Raman spectra were analyzed by fitting the A(1g)-like mode to a Lorentzian peak shape. Intrinsic dielectric parameters were estimated by fitting infrared reflectance spectra with the four-parameter semiquantum model. Transverse optic phonon mode strengths and average phonon damping were calculated. The origin of increase in the intrinsic loss with the composition variation is discussed. Microwave measurements were carried out in the frequency range of 9-11 GHz. The dielectric constant decreases and the temperature coefficient of resonant frequency becomes less negative with the increase in neodymium concentration. (c) 2008 American Institute of Physics.