Microwave dielectric properties of lanthanum based complex perovskites

Abstract

The present investigation discusses the synthesis and dielectric properties of three series of oxides of the formula La₂BaTi₂M_1−xCuxO₉ (where M = Mg, Zn and Cd). The reactions have been carried out via solid state method and all the compositions crystallize in the disordered cubic perovskite structure. Suitable substitution at both A and B sites lead to enhancement in the dielectric properties at high frequencies. The relative permittivity and loss tangent have been measured at X-band (8.2–12.4 GHz) and Ku-band (12.4–18 GHz) frequencies. The oxides show a dielectric constant of 20–30 while the dielectric loss is quite low in the order of 10⁻³–10⁻⁴ (at 500 kHz) and 10⁻² at X and Ku-band. There is scope for further investigations in these systems to realize useful materials for microwave applications.