Publications

Abstract : The effect of Co þinspace+þinspace2 doping on Cu þinspace+þinspace2 and Ti þinspace+þinspace4 sites in calcium copper titanate, CaCu 3 Ti 4 O 12 , has been examined. The doped compositions, CaCu $_{{backslash}bf 3-{backslash}emph{x}}$ Co $_{{backslash}bf {backslash}emph{x}}$ Ti 4 O 12 and CaCu 3 Ti $_{{backslash}bf 4-{backslash}emph{x}}$ Co $_{{backslash}bf {backslash}emph{x}}$ O 12 (x = 0·10) ceramics, were prepared by novel semi-wet route. In this method, calcium, copper and cobalt salts were taken in solution form and TiO 2 was used in solid form. XRD analysis confirmed the formation of single-phase materials. Structure of CaCu 3 Ti 4 O 12 does not change on doping with cobalt either on Cu-site or Ti-site and it remains cubic. Scanning electron micrographs (SEM) show average grain size of CaCu 2·9 Co 0·1 Ti 4 O 12 to be larger than CaCu 3 Ti 3·9 Co 0·1 O 12 ceramic. Energy dispersive X-ray spectroscopy (EDX) studies confined the purity of parent and Co-doped CaCu 3 Ti 4 O 12 ceramics. Dielectric constant ($ε$ r) and dielectric loss (tan $δ$) of CaCu 2·9 Co 0·1 Ti 4 O 12 is comparatively higher than that of CaCu 3 Ti 3·9 Co 0·1 O 12 ceramic at all measured frequencies and temperatures.