Strategy to achieve both enhanced dielectric tunability and reduced dielectric loss in the barium zirconium titanate ceramics

Tunable dielectric materials, serving as key components in microwave electronic application, require both high dielectric tunability and low dielectric loss. However, the trade-off between dielectric tunability and dielectric loss restricts the improvement of the overall dielectric tunability properties. In the present study, we proposed an effective approach to benefit both high tunability and low dielectric loss, i.e., improving intrinsic dielectric response from the lattice polarization and restricting the extrinsic dielectric response from the domain motions at the same time. Experimentally different acceptor dopants were employed, including the introduction of K at the A-site and Mn, Fe and Co at the B-site. On one hand, the different acceptor dopants could adjust the Curie temperature and consequently resulting in the enhanced intrinsic dielectric response at room temperature. On the other hand, the employment of acceptor dopant could introduce the oxygen vacancies and form the acceptor-oxygen vacancy dipoles which may restrict the reorientation of microdomains, resulting in the decrease of extrinsic dielectric response. Herein, both enhanced tunability and reduced dielectric loss were achieved in acceptor doped BZT ceramics at ambient temperature (27°C). In particular, Fe doped BZT ceramics achieved both high dielectric tunability of 93.8% and low dielectric loss of 0.0038. Such performance is competitive with that of previous reported dielectric tunable materials. In addition, the dielectric tunability of Fe doped BZT ceramics maintained over 60% within the wide temperature range from -20°C to 60 °C.