著者

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

出版者

公益社団法人 応用物理学会

雑誌

Japanese Journal of Applied Physics (ISSN:00214922)

巻号頁・発行日

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

被引用文献数

14

---

BaLa<SUB>4</SUB>Ti<SUB>4</SUB>O<SUB>15</SUB> (BLT) is a hexagonal perovskite-related compound with a temperature coefficient of resonant frequency (τ<SUB>f</SUB>) of −2 ppm/°C, relative permittivity (ε<SUB>r</SUB>)∼44 and figure of merit (<I>Q</I>·<I>f</I>)∼44000 GHz. Ba<SUB>4</SUB>Nd<SUB>9.333</SUB>Ti<SUB>18</SUB>O<SUB>54</SUB> (BNT) has a tungsten-bronze-related structure with ε<SUB>r</SUB>∼78, <I>Q</I>·<I>f</I>≈11000 GHz and τ<SUB>f</SUB> of +47 ppm/°C. The microstructures and microwave dielectric properties of <I>x</I>BNT–(1−<I>x</I>)BLT (0≤<I>x</I>≤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 ε<SUB>r</SUB> with respect to calculated values was observed. The optimum compositions were <I>x</I>=0.55 and 0.75 for which ε<SUB>r</SUB>∼63, τ<SUB>f</SUB>∼−20 ppm/°C and <I>Q</I>·<I>f</I>>10,000 GHz.