Phase evolution and microwave dielectric properties of A5M5O17-type ceramics

• Main Authors: Ali Murad, Iqbal Yaseen, Muhammad Raz
• Format: Article
• Language: English
• Published: Sciendo 2017-07-01
• Series: Materials Science-Poland
• Subjects: a5m5o17; dielectrics; microwave properties
• Online Access: https://doi.org/10.1515/msp-2017-0047

A number of A5M5O17 (A = Na, Ca, Sr, La, Nd, Sm, Gd, Dy, Yb; B = Ti, Nb, Ta) type compounds were prepared by a solid-state sintering route and characterized in terms of structure, microstructure and microwave dielectric properties. The compatibility of rare earths with mixed niobate/tantalate and titanate phases was investigated. The larger ionic radii mismatch resulted in the formation of pyrochlore and/or mixed phases while in other cases, pure A5M5O17 phase was formed. The samples exhibited relative permittivity in the range of 35 to 82, quality factor (Q × fo) = 897 GHz to 11946 GHz and temperature coefficient of resonance frequency (τf) = -120 ppm/°C to 318 ppm/°C.