Microwave Dielectric Properties of A 6 B 5 O 18 ‐Type Perovskites
2007; Wiley; Volume: 90; Issue: 2 Linguagem: Inglês
10.1111/j.1551-2916.2006.01456.x
ISSN1551-2916
Autores Tópico(s)Layered Double Hydroxides Synthesis and Applications
ResumoCation‐deficient perovskites with the general formula A 6 B 5 O 18 (A=Ba, Sr, La; B=Nb, Ta, Ti, Zr, Mg, and Zn) have been synthesized and their microwave dielectric properties have been investigated. X‐ray diffraction studies indicate the formation of monophase materials. The structures of Ba 6 Ta 4 TiO 18 and Ba 5 SrTa 4 TiO 18 are different from that of Sr 6 Ta 4 TiO 18 . The A 6 B 5 O 18 have Q × f in the range 5600–51 000 GHz, dielectric constants 26–48, and the temperature coefficient of resonant frequency varies from −39 to +83 ppm/°C, depending on the composition. Scanning electron microscopy studies show that the grain size decreases with an increase in the Sr content.
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