Crystal structures and microwave dielectric properties of Zn,W co-substituted BaTiO{sub 3} perovskite ceramics
- State Key Laboratory of New Ceramics and Fine Processing, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China)
Zn,W co-substituted BaTiO{sub 3} perovskite ceramics with compositions of Ba[Ti{sub 1-x}(Zn{sub 1/2}W{sub 1/2}){sub x}]O{sub 3} (x=0.40-1.00) were synthesized by the conventional solid-state reaction method and studied by X-ray diffraction and dielectric measurements. Their structures transferred from cubic (x=0.40) with space group Pm3{sup Macron }m to hexagonal (x=0.55-0.60) with P6{sub 3}/mmc, and then to cubic double pervoskite (x=1.00) with Fm3{sup Macron }m. The refinement results of sample (x=0.60) revealed that the negative and positive charge centers are not consistent with each other in the face-sharing oxygen octahedra. Compared with the cubic perovskites, the hexagonal ones had the increased quality factor (Q Multiplication-Sign f), the decreased dielectric constant ({epsilon}{sub r}), and especially the near-zero temperature coefficient of resonant frequency ({tau}{sub f}), whose absolute values were less than 5 ppm/ Degree-Sign C. The relationships between structures and properties were discussed. - Graphical abstract: The departure of the negative and positive charge centers in the face-sharing oxygen octahedra of hexagonal unit cell. Highlights: Black-Right-Pointing-Pointer A phase transition from simple cubic to hexagonal and then to cubic double pervoskite occurred. Black-Right-Pointing-Pointer Refinement results prove that spontaneous dipoles present in face-sharing oxygen octahedra. Black-Right-Pointing-Pointer Hexagonal perovskites had higher Q Multiplication-Sign f, nearer-zero {tau}{sub f}, and lower {epsilon}{sub r} than the cubic ones. Black-Right-Pointing-Pointer On the presence of the hexagonal perovskite, |{tau}{sub f}| was less than 5 ppm/ Degree-Sign C.
- OSTI ID:
- 22131183
- Journal Information:
- Journal of Solid State Chemistry, Vol. 197; Other Information: Copyright (c) 2012 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
- Country of Publication:
- United States
- Language:
- English
Similar Records
Phase relations and structural features in the system Ni-Zn-B
Mixed metallic Ba(Co,Mn)X{sub 0.2-x}O{sub 3-{delta}} (X=F, Cl) hexagonal perovskites