Dielectric and Electrical Properties of Manganese‐Doped Ag(Nb,Ta)O ₃ Ceramics Processed With Stearic Acid Additive

ABSTRACT

Silver niobate tantalate, Ag(Nb,Ta)O ₃ (ANT), is an antiferroelectric material of interest for high‐energy‐density, high‐efficiency dielectric capacitors. Its development, however, is constrained by two persistent issues: reduction of Ag ⁺ to metallic Ag ⁰ during processing, and high leakage current under applied field. Here, we examine how processing conditions and Mn‐doping influence the crystallographic phase, microstructure, and electrical properties of ANT ceramics. A powder‐processing route incorporating stearic acid as a combined lubricant and binder substantially suppressed Ag ⁰ formation relative to conventional processing, yielding phase‐pure, orthorhombic perovskite AN and ANT ceramics with relative densities exceeding 95%. The ANT55 composition achieved a breakdown strength of 665 kV/cm, giving a recoverable energy density of W _rec  = 12.3 J/cm ³ and an efficiency of η  = 86%. Doping with 1 mol% Mn lowered the sintering temperature, modestly increased permittivity, reduced dielectric loss, narrowed the P–E hysteresis loop at high field, and further increased energy‐storage efficiency at the expense of increased grain growth and reduced dielectric breakdown strength.