Ag-migration effects on the metastable phase in CaCu₃Ti₄O₁₂ capacitors

The silver migration effect into the metastable phase forms a micro-electric path, to enhance the relative dielectric permittivity of CaCu₃Ti₄O₁₂ ceramics for electronic devices. Controlling the sintering time uniquely develops the metastable phase of as-sintered CaCu₃Ti₄O₁₂ ceramics. A post-heating process that applies the migration of silver into the metastable phase increases the relative dielectric permittivity. At 1 kHz frequency, the relative dielectric permittivity at room temperature of the silver-migrated CaCu₃Ti₄O₁₂ ceramics sintered for 2 h is 565.9 × 10³, almost 52 times higher than that of the as-sintered CaCu₃Ti₄O₁₂ ceramics. The selected area electron diffraction (SAED) patterns of the large and small grains were similar, but differed from those of the metastable region, including the grain boundary of the as-sintered CaCu₃Ti₄O₁₂ ceramics sintered for 2 h by TEM technique. This phenomenon suggests that enabling Ag-migration into the metastable phase develops a micro-electric path that improves the relative dielectric permittivity of CaCu₃Ti₄O₁₂ ceramics.