著者

Zheng Hong Reaney Ian M. Muir Duncan Price Tim Iddles David M.

出版者

Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physics

雑誌

Japanese journal of applied physics. Pt. 1, Regular papers & short notes (ISSN:00214922)

巻号頁・発行日

vol.44, no.5, pp.3087-3090, 2005-05-15

被引用文献数

14

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BaLa4Ti4O15 (BLT) is a hexagonal perovskite-related compound with a temperature coefficient of resonant frequency ($\tau_{\text{f}}$) of $-2$ ppm/°C, relative permittivity $(\varepsilon_{\text{r}})\sim 44$ and figure of merit $(Q\cdot f)\sim 44000$ GHz. Ba4Nd9.333Ti18O54 (BNT) has a tungsten-bronze-related structure with $\varepsilon_{\text{r}}\sim 78$, $Q\cdot f\approx 11000$ GHz and $\tau_{\text{f}}$ of $+47$ ppm/°C. The microstructures and microwave dielectric properties of $x$BNT–($1-x$)BLT ($0\leq x\leq 1$) composite ceramics have been studied. X-ray diffraction analysis and scanning electron microscopy revealed that there was limited inter-reaction between the two phases and that samples were composed largely of BNT and BLT, although some deterioration in measured $\varepsilon_{\text{r}}$ with respect to calculated values was observed. The optimum compositions were $x=0.55$ and 0.75 for which $\varepsilon_{\text{r}}\sim 63$, $\tau_{\text{f}}\sim-20$ ppm/°C and $Q\cdot f>10{,}000$ GHz.