A novel self-composite property-tunable LaTiNbO6 microwave dielectric ceramic

•Self-composite property-tunable LaTiNbO6 ceramics were obtained by post-annealing.•Near-zero τf was yielded in the sample with one-hour annealing.•Orthorhombic LaTiNbO6 phase with a high εr and a positive τf was first reported.•A special microstructure evolution was disclosed by a novel self-healing process.•A novel concept of ‘self composite’ was proposed in microwave dielectric ceramics.

A novel self-composite LaTiNbO6 microwave dielectric ceramic was fabricated via a solid-state reaction method together with an annealing process. A monoclinic LaTiNbO6 after a conventional sintering was found to gradually transform into an orthorhombic counterpart with prolonging annealing time. Microwave dielectric properties of ceramics can be easily tailored by changing the relative content of two coexisting phases with complementary performances. A thermal-stable dielectric ceramic (εr = 30.2, Q × f = GHz) was yielded after annealing at 1100 °C for 1 h. The concept of the self composite might provide an innovative and simple way to develop property-tunable microwave dielectric ceramics.

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