Microstructural, structural and dielectric properties of Er~(3+) -modified BaTi_(0.85)Zr_(0.15)O_3 ceramics

摘要

The (micro)structural and electrical properties of undoped and Er~(3+) -doped BaTi_(0.85)Zr_(0.15)O_3 ceramics were studied in this work for both nominal Ba~(2+) and Ti~(4+) substitution formulations. The ceramics were produced from solid-state reaction and sintered at 1400 deg C for 3 h. For those materials prepared following the donor-type nominal Ba_(1-x)Er_x(Ti_(0.85)Zr_(0.15))O_3 composition, especially, Er~(3+) 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)O_(3-delta)-like system, with a solubility limit below but close to 3 cat. percent Er~(3+) The overall phase development is discussed in terms of the amphoteric nature of Er~(3+) , 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 Er~(3+) content.