Modeling of the core-shell microstructure of temperature-stable BaTiO3 based dielectrics for multilayer ceramic capacitors

A simplified model was proposed for the core-shell microstructure, which existed in the temperature-stable BaTiO3 (BT) based dielectrics for multilayer ceramic capacitors (MLCCs) and was regarded as the reason resulting in the temperature-stable characteristics. In this model the capacitance of a core-shell grain can be regarded as the parallel combination of the capacitance of the grain core and the grain shell. To verify the validity of the model, core material, shell material and core-shell material were prepared. Based on our previous work, BT with a grain size of 400 nm was chosen as the core material; X7R material milled for 1 hour was chosen as the core-shell material; doped BT milled for 36 h was chosen as the shell material. The calculated results showed good agreement with the measured experimental results of the core-shell material, which proved the validity of the model.

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