Siam Physics Congress 2015

Influences of Sn Doping and CaTiO${}_3$ Volume Fraction on Microstructure and Electrical Response of Sn-doped CaCu${}_3$Ti${}_4$O${}_{12}$/CaTiO${}_3$ Composites

21 May 2015, 13:00

3h 30m

Board: MNA-16

Poster presentation Material Physics, Nanoscale Physics and Nanotechnology Poster-3

Speaker

Mr Jutapol Jumpatam (Materials Science and Nanotechnology Program, Faculty of Science, Khon Kaen University, Khon Kaen, THAILAND 40002)

Description

The influences of Sn doping concentration and CaTiO$_3$ volume fraction on microstructure and electrical response of Sn-doped CaCu$_3$Ti$_4$O$_{12}$/CaTiO$_3$ composites prepared from a nominal formula of Ca$_{1+x}$Cu$_{3-x}$Ti$_{4-y}$Sn${}_y$O${}_{12}$ (where $x$ = 0, 0.5, 1 and 1.5; $y$ = 0.05 and 0.30) were investigated. The dielectric properties of CaCu${}_3$Ti${}_4$O${}_{12}$/CaTiO${}_3 $ composites were measured as functions of frequency and temperature. The n-type semiconducting grains of CaCu${}_3$Ti${}_4$O${}_{12}$ phase and insulating interfaces between CaCu${}_3$Ti${}_4$O${}_{12}$-CaCu${}_3$Ti${}_4$O${}_{12}$ grains and CaCu${}_3$Ti${}_4$O${}_{12}$-CaTiO${}_3$ grains were studied by an impedance spectroscopy technique. The microstructure of Ca${}_{1+x}$Cu${}_{3-x}$Ti${}_{4-y}$Sn${}_y$O${}_{12}$ ceramics was slightly changed with increasing CaTiO${}_3$ volume fraction. The dielectric properties were strongly affected by Sn content and the volume faction of CaTiO${}_3$. At 1 kHz, the dielectric constant (${\varepsilon}^{\prime}$) increased with increasing Sn doping concentration. It was also found that ${\varepsilon}^{\prime}$ decreased with increasing CaTiO${}_3$ volume fraction. The activation energy for conduction within the grains slightly increased with increasing the Sn content; whereas, the activation energy for conduction at the internal interfaces decreased slightly. Interestingly, it was found that Egb increased significantly with increasing CaTiO${}_3$ volume fraction.