Ba3La3Ti4NbO18: a new microwave dielectric of A6B5O18-type cation-deficient perovskites

A new A6B5O18-type cation-deficient perovskite Ba3La3Ti4NbO18 was prepared by the conventional solid-state reaction route. The phase and structure of the ceramics were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM). The compound crystallizes in the trigonal system with unit cell parameter a=5.6198(1) Å, c=41.6402(4) Å, V=1138.90(1) Å3, and Z=3. The microwave dielectric properties of the ceramic were studied using a network analyzer, and it shows a high dielectric constant of 47.44, a high-quality factors with Q×f of 17,729 GHz, and a positive τf of +35.2 ppm °C−1.