Controllable-permittivity and high-tunability of Ba0.5Sr0.5TiO3/MgO based ceramics by composite configuration

Abstract

Ba0.5Sr0.5TiO3 (BST50)/MgO composites, with 2-2-type configurations, consisting of BST layers and MgO layers, were fabricated by using tape-casting and laminating technique. Microstructure, dielectric response, and tunable properties of the 2-2-type composites were investigated. An important feature of the 2-2 type composites is that DC fields can be effectively applied to the high-permittivity ferroelectric phase when the fields are applied in parallel direction to the inter-phase boundaries. As a result, with increasing volume fraction (q) of MgO, tunability of the composites remained almost unchanged, whereas their permittivity value could be reduced significantly. This behavior has not been observed in the conventional 3-0 type composites.

Study of the role of porosity on the functional properties of (Ba,Sr)TiO 3 ceramics

“…Ni, Y, Bi, Ga, Mn, Fe, etc. ), tunability of the resulted compounds can be preserved, whereas their permittivity (e) value could be reduced [16][17][18][19][20][21]. In order to obtain the desired characteristics which are not compatible with the pure phase material and to avoid the unwanted chemical reactions that could take place at the interfaces when combining dissimilar materials, the approach to develop porous ceramics was also proposed [22][23][24].…”

“…The dielectric properties of ferroelectric ceramics could be significantly modified by doping, by forming solid solutions or composites with other materials [14][15][16][17][18][19][20][21]. The ''dilution'' of their dielectric constant and minimization of the dielectric loss of BST-based materials can be achieved by adding amounts of non-ferroelectric dielectrics.…”

Fabrication and Microwave Dielectric Properties of Mg2SiO4‐LiMgPO4‐TiO2 Composite Ceramics

“…2(a). The diffraction peak of [130] moves to higher angle with the increasing content of LiMgPO 4 and it reveals that the related lattice parameters decrease. The lattice parameters are determined by the Rietveld refinement method, and the cell volume decreases with the increasing content of LiMgPO 4 as shown in Fig.…”

“…These applications demand microwave substrate materials with high‐quality factor ( Q × f ) to achieve high selectivity, low dielectric constant (ε r ) to reduce the delay time of electronic signal transmission, and almost zero temperature coefficient of resonant frequency (τ f ) for frequency stability. In the past years, a large number of ceramics with good microwave dielectric properties have been reported as promising candidates for substrate application, such as Mg 2 SiO 4 ( Q × f = 240 000 GHz, ε r = 6–7, τ f = −60 ppm/°C), Al 2 O 3 (tanδ = 2.7 × 10 −5 at 10 GHz, ε r = 10), MgO (ε r = 7–10, Q × f = 113 600 GHz), and Li 2 MgSiO 4 (tanδ = 5.2 × 10 −4 at 8 GHz, ε r = 5.1) . Among these materials, forsterite Mg 2 SiO 4 has attracted a great attention with low dielectric constant and high‐quality factor …”

“…19 It is interesting to tune the chemical compatibility between Mg 2 SiO 4 and TiO 2 by incorporating LiMgPO 4 . In this paper, solid solutions of Mg 2 SiO 4 -LiMgPO 4 were investigated together with their chemical compatibilities with rutile phase. Microwave dielectric properties were also investigated for ceramics of (1Ày) [0.5Mg 2 SiO 4 -0.5LiMgPO 4 ]-yTiO 2 (y = 0-0.3).…”