Microwave Dielectric Properties of Temperature-Stable BaLn2(MoO4)4–TiO2 (Ln = Ce, Nd, and Sm) Ceramics

Abstract

A series of temperature-stable microwave dielectric ceramics (1 − x)Ba Ln2(MoO4)4–xTiO2 (Ln = Ce, Nd, and Sm; 0.4 ≤ x ≤0.55) were prepared by solid-state reaction. Sintering behavior, phase composition, microstructure, and microwave dielectric properties were investigated. X-ray powder diffraction and scanning electron microscopy revealed that the main phases of the BaLn2(MoO4)4–TiO2 ceramics were the monoclinic BaLn2(MoO4)4 phase and the rutile TiO2 phase. Study of the materials’ microwave dielectric properties revealed that the permittivity (e r) and the temperature coefficient of the resonant frequency (τ f) increased gradually with increasing x value whereas quality factors (Q × f) decreased. For BaLn2(MoO4)4–TiO2 (Ln = Ce and Nd), τ f values could be adjusted to near zero, relative permittivity (e r) was 13.2–14.3, and Q × f values were between 11,950 and 45,720 GHz (at 9.11–9.83 GHz) when x = 0.45 to 0.55. For BaSm2(MoO4)4–TiO2, excellent microwave dielectric properties were obtained when x = 0.4 to 0.5, τ f values could be adjusted to near zero, e r was 13.1–13.9, and Q × f values were between 25,520 and 63,130 GHz (at 9.31–10.11 GHz).