Microwave Dielectric Properties and Thermally Stimulated Depolarization Currents of (1−x)Ba(Mg_1/3Nb_2/3)O₃–xBaSnO₃ Solid Solutions

Abstract

Microwave dielectric ceramics of (1−x)Ba(Mg1/3Nb2/3)O3‐xBaSnO3 [(1−x)BMN‐xBS] with high quality factors was synthesized by the solid‐state reaction method. The effects of BaSnO3 additions (x = 0–0.2) on the sinterability, crystal structures, microwave dielectric properties, and microwave dielectric loss mechanisms of BMN were investigated systematically. The degree of 1:2 cation ordering was decreased with increasing Sn content and eventually faded away as x ≥ 0.1, where the low‐temperature relaxations disappeared coincidently through the thermally stimulated depolarization current technique. It was supposed to be the short‐range misplacements of the B‐site cations within the long‐range ordered structure. Meanwhile, the high‐temperature relaxations associated with the in‐grain oxygen vacancies were found in all the title compounds. Though the concentrations of oxygen vacancies of 0.8BMN‐0.2BS were higher than BMN, high Q × f values could also be obtained even in the absence of 1:2 cation ordering. Specifically, the excellent characteristics like εr = 29.02, Q × f = 90 000 GHz and τf = 6.3 ppm/°C were achieved in the specimens of x = 0.2 sintered at 1450°C.

Microwave dielectric properties and thermally stimulated depolarization of Al‐doped Ba4(Sm,Nd)9.33Ti18O54 ceramics

“…However, the Q × f values of current microwave dielectric ceramics still do not meet the requirements for 5G communication. Many attempts have been made to improve the Q × f values of microwave dielectric ceramics, such as introducing dopants to form solid solutions, using nonstoichiometric effects, and adding foreign components with higher Q × f values . However, the related microwave dielectric loss mechanism remains unclear, and the increase in Q × f values is often accompanied by the deterioration of other properties (especially ε r ) .…”

“…The microwave dielectric properties of Ba 4 (Sm 0.15 Nd 0.85 ) 9.33 Ti 18‐ z Al 3 z /4 O 54 (BSNT‐ z Al) ceramics and their correlation with the z value were determined. In addition, the thermally stimulated depolarization current (TSDC) technique can provide semiquantitative information of dielectrics on the types (such as trap charges, defect dipoles, and space charges), concentrations, and activation energies of the defects . At present, TSDC has been widely used to clarify the polarization mechanism of various types of dielectric ceramics and to explore the relationships between defects and dielectric performance.…”

“…10,11 However, the related microwave dielectric loss mechanism remains unclear, and the increase in Q × f values is often accompanied by the deterioration of other properties (especially ε r ). [2][3][4][5][6] Therefore, it is still a challenge to improve the Q × f values of microwave dielectric ceramics.…”

“…In addition, the thermally stimulated depolarization current (TSDC) technique can provide semiquantitative information of dielectrics on the types (such as trap charges, defect dipoles, and space charges), concentrations, and activation energies of the defects. 2,10,[19][20][21][22][23][24][25][26][27] At present, TSDC has been widely used to clarify the polarization mechanism of various types of dielectric ceramics and to explore the relationships between defects and dielectric performance. In this study, the TSDC technique was also used to study the underlying defects and their effects on the microwave dielectric properties in the BSNT-zAl ceramics.…”

Crystal structure, defect relaxation, and microwave dielectric properties of Ba[(Mg1/3Nb2/3)1−xHfx]O3 solid solutions

“…However, tantalum is a relatively expensive metal . Because of the high price and limitation of Ta resources, it has resulted in seeking for alternative materials . Among them, the Nb‐analog has received much attention, including columbites ANb 2 O 6 (A = Zn, Mg, Co), complex perovskites Ba(Zn 1/3 Nb 2/3 )O 3 (BZN), and Ba(Mg 1/3 Nb 2/3 )O 3 (BMN) …”