Crystallographic study, by Rietveld's method, of barium - magnesium - tantalum oxides based ceramics for use as dielectric resonator. X-ray dilatometry at low temperature

Cation Ordering Types and Dielectric Properties in the Complex Perovskite Ca(Ca1/3Nb2/3)O3

“…This can be realized by displacements of the B-cations along the 11 1 1 2 direction toward the B-occupied +1 1 1, cation plane. Such displacements indeed have been observed in the Ba(Mg Ta )O structure (21), where bond valences calculated from the re"ned cation}oxygen bond distances (s Mg}O1 "0.33 v.u., s Ta}O1 "0.99 v.u., s Ta}O2 "0.65 v.u.) are in good agreement with the predicted values.…”

Low Loss Dielectrics in Ba[(Mg1/3Ta2/3)1−xTix]O3 and Ba[(Mg1−xZnx)1/3Ta2/3]O3 Systems

“…In that report, the dielectric properties of BMT containing 1.0 mol% Mn addititive were ⑀ r ‫ס‬ 25, f ‫ס‬ 4.4 ppm/°C, and Q u ‫ס‬ 16,800 at 10.5 GHz, while those of BZT were ⑀ r ‫ס‬ 30, f ‫ס‬ 0.6 ppm/°C, and Q u ‫ס‬ 14,500 at 11.4 GHz. However, the structural ordering behavior of these compounds are different; in 1993 Vincent et al 11 showed that BMT exhibits only partial ordering whereas BZT is fully ordered. 12 A significant contribution in this regard was made by Ohuchi et al, 13 who observed an anomalous variation of the microwave quality factor in BMT-BZT solid solution phases.…”

Synthesis of Ba3ZnNb2O9−Sr3ZnNb2O9 solid solution and their dielectric properties

“…Ba 3 ZnTa 2 O 9 was the first low loss dielectric material reported (Kawashima et al 1983) for application at microwave frequencies. Since then several studies (Nomura et al 1982;Desu and O'Bryan 1985;Vincent et al 1993) on related oxides have been carried out on other tantalates. These oxides crystallize in the disordered cubic structure or in a hexagonally ordered structure.…”