Modulation of rare-earth diffusion for tailoring diverse MLCC application requirements

Abstract

This study demonstrates that the low shell-forming temperatures of Mg in powdered form can effectively control Dy diffusion into BaTiO₃. For Dy pre-coated BaTiO₃, the insulation resistance is higher due to an increased shell thickness compared to Mg pre-coated BaTiO₃. However, the thermal activation energy and ohmic conduction slope exhibit comparable values for both Dy and Mg pre-coated BaTiO₃. Moreover, the high resistance and low dielectric permittivity observed in Dy pre-coated BaTiO₃ are attributed to B-site substitution of BaTiO₃ by the significant Dy dopant content. In contrast, the high coercive field and low resistance for Mg pre-coated BaTiO₃ result from Dy aggregation caused by inhibited Dy diffusion. This study offers valuable insights into optimizing rare-earth element diffusion strategies to satisfy diverse application requirements in multilayer ceramic capacitors.