The Influence of Doped MgF₂ on the Dielectric Properties of Barium Strontium Titanate Ceramics

Abstract:

Barium-strontium titanate Ba_1-xSr_xTiO₃ [0≤x≤1] has been investigated for tunable microwave application due to their high permittivity, low losses and high tunability. The influence of MgF₂ additives on the dielectric performance of Ba_0.6Sr_0.4TiO₃ (BSTO) were investigated in this paper. MgF₂ doped BSTO ceramics were prepared using the conventional mixed oxide techniques. The phase structure, microstructure and dielectric properties of MgF₂ doped BSTO ceramics were studied. The XRD patterns showed that all the samples exhibit a perovskite phase. A secondary phase of MgO was observed with excessive MgF₂ additives. The grain size of MgF₂ doped BSTO ceramics was slightly increased with the increasing of MgF₂ additives, while the distributed porosity was concentrated to get larger. The relative permittivity, dielectric loss and tunability were decreased accordingly. The relative permittivity was reduced from 3717 (pure Ba_0.6Sr_0.4TiO₃) to 680 (6 wt % MgF₂ doped BSTO), while the tunability changed from 51.7 % to 6.5 %. The dielectric losses were decreased from 0.004 to less than 0.001. The Curie temperature of MgF₂ doped BSTO was first decreased with the additives of MgF₂ (x<2 wt %) then remain the same with the rise of MgF₂ (2≤x≤6) content.

• Periodical: Materials Science Forum (Volume 687)
• Pages: 427-432
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.687.427
• Online since: June 2011
• Authors: Shan Shan Liu, Yu Zhen Zhao, Xi Lin Wang, He Ping Zhou
• Keywords: Barium Strontium Titanate, Doped, Magnesium Fluoride, Tunability

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DOI: 10.1016/b978-012544415-6.50087-x

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