Abstract
The microwave dielectric properties of the series Pb n Nb 2 O 5+ n (1.3 ≤ n ≤ 3.0) have been established in this work. Single-phase cubic pyrochlore was obtained for n = 1.5. Compositions for which n > 1:5 showed discreet PbO-rich layers between alternating slabs of pyrochlore, similar in appearance to Ruddlesden–Popper phases. These layers have a profound effect on the microwave properties, with n = 2 yielding the lowest τ f (814 ppm/ºC) in the series. Attempts were made to reduce τ f further by both Mg- and Ta-doping. The properties of Mg-doped Pb 1.5 Nb 2 O 6.5 were investigated for several concentrations of Mg (on the Nb site) up to Pb 1.5 (Mg 0.24 Nb 1.76 )O 6.14 , but none showed great promise. Isovalent doping with Ta, Pb n Ta x Nb 2-x O 5+ n , was much more successful. Both the n = 1.5 as well as the n = 2 compositions showed a marked decrease in τ f with an increasing amount of Ta.
| Original language | American English |
|---|---|
| Pages (from-to) | 2659-2662 |
| Number of pages | 4 |
| Journal | Journal of the European Ceramic Society |
| Volume | 21 |
| Issue number | 15 |
| DOIs | |
| State | Published - 2001 |
Keywords
- Dielectric properties
- Niobates Pyrochlores
- Tantalates
EGS Disciplines
- Materials Science and Engineering