Dielectric property of Ba0.6Sr0.4TiO3–Mg0.9Zn0.1O ceramic with additives of Sm2O3 and Ta2O5

Abstract

Influence of Sm2O3 and Ta2O5 additions on the dielectric property of Ba0.6Sr0.4TiO3–Mg0.9Zn0.1O (BST–MZO) ceramic composite was investigated. The XRD results indicate that the main phases in the Sm2O3 and Ta2O5 doped samples are BST and MZO. Loss tangent of BST–MZO ceramic becomes higher with additive of Sm2O3. Optimum doping amount of Ta2O5 can reduce loss tangent of BST–MZO ceramic which can also ensure the moderate dielectric constant and usable tunability. When the amount of Ta2O5 is 1.0 wt%, the dielectric constant, loss tangent and tunability are 84.85, 0.0005 (at 1 MHZ) and 15% (under electric field 7 kv/mm), respectively. At microwave frequency (4.025 GHz), the dielectric constant decreases to 81.03 while loss tangent increases to 0.0049. The ceramic with additive of 1.0 wt% Ta2O5 has the optimal FOM value (about 261) and should be a promising candidate for phase shifter application.