Dielectric tunability of Ba_0.6Sr_0.4TiO₃–Li₂Mg₃SnO₆ ceramics with ultralow loss

Ba_0.6Sr_0.4TiO₃-based (BST) tunable dielectric ceramics have shown their advances in modern electronic devices. However, limited by high dielectric permittivity (ε_r) and loss (tanδ) of BST, BST-based ceramics are far from practical tunable applications. This study focuses on a low dielectric permittivity and loss composition, Li₂Mg₃SnO₆ (LMS), to optimize the dielectric tunability performance of BST. A series of (1−x)BST-xLMS (x = 10, 20, 30 wt.%) ceramics were successfully prepared and studied. Phase analysis suggests LMS mainly merges into the perovskite phase, and dielectric properties studies reveal a decrease in the Curie temperature of BST, along with decreased dielectric permittivity at room temperature. The measured dielectric tunabilities are 13.3, 7.8, 4.5% with ε_r of 903, 560, 418, and tanδ all <10⁻³ of x = 10, 20, 30 wt.%, respectively. This study demonstrates that LMS could effectively manipulate the overall dielectric tunability performance of BST while possessing ultralow loss, offering an insight into optimizing the dielectric loss of dielectric materials.