Improving dielectric properties of (Zn2+, Al3+) Co-doped CaCu3Ti4O12 perovskite ceramics by enhancing the grain boundary response.

CaCu 3 Ti 4 O 12 and CaCu 2.95 Zn 0.05 Ti 4- x Al x O 12 (x = 0.025, 0.05, and 0.10) ceramics were created using a conventional solid-state reaction method. A single phase of CaCu 3 Ti 4 O 12 was present in all ceramics. Co-doping with Zn2+ and Al3+ resulted in a significantly increased grain size. According to the DFT results, both Zn and Al atoms preferentially occupy Cu sites, resulting in LPS processes caused by excess Cu concentrations at the grain boundary. CaCu 2.95 Zn 0.05 Ti 4- x Al x O 12 ceramics with dielectric permittivities of more than 7.00 × 104 and dielectric loss tangents less than 0.04 have been produced. It was also discovered that the temperature stability of dielectric permittivity could be boosted. Improved electrical properties of grain boundaries, particularly grain boundary resistance, in co-doped ceramics caused by the influence of metastable phases such as Cu-related phases and oxygen enrichment at the grain boundaries, might well be related to improved dielectric properties. The Cu-related phases and the structure without oxygen vacancy at the grain boundary can act as a stable insulative layer, preventing long-range charge migration. From our electron density calculations, the Zn and Al ions become more positive, whereas the O ions are more negative. Moreover, Cu+ and Ti3+ could be generated from the V O ++ in the Zn05Al10 structure. Based on experimental and theoretical data, an internal barrier layer capacitor structure in these ceramics could account for the giant dielectric characteristics of these materials. [ABSTRACT FROM AUTHOR]