Microstructural, structural and dielectric properties of Er3+-modified BaTi0.85Zr0.15O3 ceramics

The (micro)structural and electrical properties of undoped and Er3+-doped BaTi0.85Zr0.15O3 ceramics were studied in this work for both nominal Ba2+ and Ti4+ substitution formulations. The ceramics were produced from solid-state reaction and sintered at 1400 °C for 3 h. For those materials prepared following the donor-type nominal Ba1−xErx(Ti0.85Zr0.15)O3 composition, especially, Er3+ however showed a preferential substitution for the (Ti,Zr)4+ lattice sites. This allowed synthesis of a finally acceptor-like, highly resistive Ba(Ti,Zr,Er)O3−δ-like system, with a solubility limit below but close to 3 cat.% Er3+. The overall phase development is discussed in terms of the amphoteric nature of Er3+, and appears to mainly or, at least, partially also involve a minimization of stress effects from the ion size mismatch between the dopant and host cations. Further results presented here include a comparative analysis of the behavior of the materials’ grain size, electrical properties and nature of the ferroelectric-to-paraelectric phase transition upon variation of the formulation and Er3+ content.