Combustion-synthesized ferrites and ferroelectrics for microwave applications

The individual phases of Ni1 − xCdxFe2O4 (x = 0.2, 0.4, 0.6) ferrite and Ba0.8Sr0.2TiO3 ferroelectric (BST phase) were successfully prepared by autocombustion route. The oscillatory behavior of transmittance for the Ni-Cd ferrite was observed at about 0.44 at 8.2 GHz. The absorption study depicts the hopping phenomena of microwaves through the Ni-Cd phase. The dependence of microwave conductivity on ferrite content was discussed. The dielectric permittivity of Ni-Cd ferrites varied between 10 and 30. Compared to the Ni-Cd phase, the transmittance of the Ba0.8Sr0.2TiO3 phase was found to be low. The dip in reflection loss for Ba0.8Sr0.2TiO3 is equivalent to the minimum reflection or the maximum absorption of the microwave power for BST phase. The maximum microwave conductivity for Ba0.8Sr0.2TiO3 was found to be about 0.459 S/cm. The high microwave permittivity for Ba0.8Sr0.2TiO3 had a value of about 120.21.