Temperature Coefficient of Dielectric Constant in CaTiO3-A(B′, B″)O3 Microwave Dielectric Ceramics (A=Ca, La, Li, B′=Al, Fe, Mg, B″=Nb, Ta) |
Jeong-Seog Kim, Chae-Il Cheon, Chan-Sik Park1, Jae-Dong Byun2 |
Department of Materials Science and Engineering, Hoseo University 1R & D Center, Acetronix Co. 2Department of Materials Engineering, Korea University |
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ABSTRACT |
The dielectric polarizability-related factors contributing to the $tau$$_{varepsilon}$ have been analysed in terms of dielectric permittivity $varepsilon$, Tolerance Factor (TF), and octahedron tilt angles in (1-x)CaTi $O_3$-x[A(B', B″) $O_3$] (A=Ca, La, Li, B'=Al, Fe, Mg, B″=Nb, Ta) and (S $r_{0.2}$C $a_{0.8}$)( $Ti_{1-x}$ Z $r_{x}$) $O_3$. All the compounds have the orthorhombic Pbnm structure except the end members A(B', B″) $O_3$ and the solid solutions of x$geq$0.8. The additional dipole field effect is suggested as a dominant factor contributing to $tau$$_{varepsilon}$ in CaTi $O_3$-based ceramics having relatively large $varepsilon$, which has not been generally considered in the previous reports dealing with the $tau$$_{varepsilon}$. This study has been focussed on delineating the dipole field effect on the $tau$$_{varepsilon}$ in comparison to the octahedron tilt effect in CaTi $O_3$-based ceramics.cs..cs. |
Key words:
Temperature coefficient of dielectric constant, Crystal structure, Dipole field effect, Octahedron tilt angle, $CaTiO_3$-based perovskite |
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