La、Cr 掺杂对钛酸锶钡陶瓷调谐性能的影响

To meet the requirements of tunable microwave devices for high dielectric tunability and low dielectric loss, (Ba0.67sSr0.325) 1-0.005 La0.005 Tii-^Cr^Os (x: 0. 3%, 0.5%, 0.7%, 1.0%) ceramics with excellent tunable performance were designed and prepared using the conventional solid-state reaction method. Donor dopant La was added to replace Ba/Sr to improve the dielectric tunability while acceptor dopant Cr was introduced to replace Ti to reduce the dielectric loss. The effect of La/Cr doping ratio on the microstructure and electrical properties of BST ceramics was investigated. The experimental results showed that with an increase in the acceptor dopant content, both the grain size and relative density exhibited an initial increase followed by a subsequent decrease. It can be concluded that a suitable doping ratio could be benifited dense microstructure. The optimal tunable properties were observed at Cr3+ mole fraction of 0. 7%, yielding a high dielectric tunability of 83. 6%, a reduced dielectric loss of 0. 004 1, and a figure of merit of 204. In this case, the breakdown strength reached 14 kV/mm. The research findings could provide guarantees for the working stability of materials under high applied electric field.