Abstract
Impedance analyses was performed on undoped and Nb-doped CaCu3Ti4O12 (CaCu3Ti4−xNbxO12+x/2; x = 0,
0.01, 0.03, 0.05, 0.1) to investigate their electrical properties. The
pellet samples were prepared using the solid state reaction method.
Silver electrode was deposited on both pellets’ surfaces for electrical
measurement. The thermally etched samples showed tiny bumped domains
within the grains. The existence of both domain and grain boundaries are
believed to strongly influence the dielectric constant of CaCu3Ti4O12
(CCTO). Undoped CCTO showed two arcs of impedance complex plane while
Nb-doped samples have three arcs. Each arc represents the constituent
elements of the CCTO. The highest frequency arc is evidence that CCTO
consists of conductive domains which measure about 1 Ω and are insulated
by two types of barriers, i.e. domain boundary and grain boundary.
Highlights
►
The thermally etched samples show tiny bumped domains within grain. ►
The existence of both domain and grain boundaries are believed to
strongly influence the dielectric constant of CCTO. ► Nb-doped CCTO give
three arcs of impedance complex plane measured in the range frequency
of 1 Hz to 1 GHz. ► Each arc represents the constituent elements of the
CCTO. ► The highest frequency arc is evidence that CCTO consists of
conductive domains which about 1 Ω and are insulated by two types of
barrier, i.e. domain boundary and grain boundary.
Keywords
- Powders-solid state reaction;
- Grain boundaries;
- Dielectric properties;
- Impedance;
- Perovskites
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