Composite Dielectric Ceramics Based on BaO–Ln2O3–TiO2 (Ln = Nd, La)

概要

論文の詳細を見る
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.
2005-05-15