Microwave Dielectric Properties and Structure of the Ba_6-3xSm_8+2xTi₁₈O₅₄ Solid Solutions

Abstract

The microwave dielectric properties of the Ba 6-3 x Sm 8+2 x Ti 18 O 54 (0.3≤ x ≤0.7) solid solutions are studied in relation to the crystal structure. Q · f of suitable materials obtained by optimizing the sintering condition is in inverse proportion to the dielectric constant ( ε r ). With increase of x , ε r decreased and Q · f increased. Good-quality microwave resonators with ε r =80 and Q · f =9720 GHz can be obtained in the composition range of x =0.5 to 0.7 in the solid-solution region. Substitution of 2Sm 3+ for 3Ba 2+ in the large cation sites results in the creation of vacancies and crystal distortion, showing that the shrinkage of the TiO 6 octahedral site plays an important role for improvement of the microwave dielectric properties.