Microwave Dielectric Properties of Ca₄ La₂ Ti_{5− x}( Mg_1/3 Nb_2/3)_x O₁₇ Ceramics.

Chen, Guo-hua; Di, Jie-chang; Xu, Hua-rui; Jiang, Min-hong; Yuan, Chang-lai; Tan, X.

Using the solid-state ceramic route, Ca4 La2 Ti5− x( Mg1/3 Nb2/3) x O17 (0 ≤ x ≤ 4) ceramics were prepared, and the phase purity, microstructure, and microwave dielectric properties were investigated. The XRD results suggest the formation of solid solutions for all studied compositions (0 ≤ x ≤ 4) and the unit cell volume increases linearly with x. The SEM results also show no evidence of secondary phase and doping ( Mg1/3 Nb2/3) at Ti site promotes the grain growth. The εr of sintered ceramics decreases from 71.86 to 35.23, the Q × f value increases from 15 070 to 21 277 GHz and the τ f value varies from 125.2 to −16.7 ppm/°C with x increasing from 0 to 4. A near-zero τ f (~1.62 ppm/°C) is achieved at x = 3 with εr ~ 40.45 and Q × f ~ 19 123 GHz.

Journal of the American Ceramic Society, 2012, Vol 95, Issue 4, p1394

0002-7820

Academic Journal

10.1111/j.1551-2916.2011.05004.x