Lattice vibrational characteristics and dielectric properties of pure phase CaTiO 3 ceramic
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Lattice vibrational characteristics and dielectric properties of pure phase CaTiO3 ceramic Feng Shi1,2,*
, Guang-en Fu2, En-Cai Xiao2, and Jianzhu Li3
1
Key Laboratory of Processing and Testing Technology of Glass & Functional Ceramics of Shandong Province, School of Materials Science and Engineering, Qilu University of Technology (Shandong Academy of Sciences), Jinan 250353, China 2 School of Material Science and Engineering, Shandong University of Science and Technology, Qingdao 266590, China 3 School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209, China
Received: 6 July 2020
ABSTRACT
Accepted: 26 August 2020
CaTiO3 microwave dielectric ceramic was fabricated utilizing traditional twostep sintering process. XRD pattern analysis after Rietveld refinement indicated a pure phase CaTiO3 sample. SEM image illustrated well-crystallized sample with uniform grain sizes and clear grain boundaries. The lattice vibrational characteristics were analyzed by Raman and IR spectroscopy, and the intrinsic properties were calculated in conjunction with the semi-quantum four-parameter (FPSQ) model, which turned out that the low-frequency vibrational modes contribute the most to the dielectric properties. Besides, the real and imaginary parts of the dielectric function were drawn from the FPSQ model. The intrinsic property results fitted from the FPSQ model agree well with the measured values.
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Springer Science+Business
Media, LLC, part of Springer Nature 2020
1 Introduction In recent decades, mobile communication products have gradually evolved towards miniaturization, high efficiency, integration, and low loss [1]. Therefore, the application of microwave dielectric ceramics (MWDCs) has attracted widespread attention. As the role of dielectric ceramics in the mobile communication industry becomes more and more important, the market also has higher requirements for the performance and quality of dielectric ceramics [2, 3]. For
instance, the MWDCs fetched to manufacture resonators and filters are required to possess the following attributes: a higher dielectric constant (er) is conducive to miniaturization of the device, a higher quality factor (Q 9 f) ensures excellent filtering characteristics and communication quality, a frequency temperature coefficient of resonant frequency (sf) close to zero endows the devices in possession of excellent temperature stability [4–6]. In the light of Yashima’s research results [7], CaTiO3 possesses an orthorhombic structure at room temperature and belongs to the Pbnm space group.
Feng Shi, Guang-en Fu and En-Cai Xiao contributed equally to this work and should be considered co-first authors.
Address correspondence to E-mail: [email protected]
https://doi.org/10.1007/s10854-020-04357-9
J Mater Sci: Mater Electron
Phase transition will occur along with the temperature rising, that is, when the temperature rises to about 1512 K, CaTiO3 will change to the tetragonal structure belonging to the I4/mcm space group, and when the temperat
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