Chemical synthesis of cubic bismuth zinc niobate ceramic and its dielectric properties

Powders of (Bi(3/2)Zn(1/2))(Zn(1/2)Nb(3/2))O(7) (BZN) were prepared by the polymerised complex method, based on the Pechini type reaction route. The crystallisation process of BZN during the calcination of an amorphous precursor was observed, using thermogravimetric and differential scanning calorimetric analysis and X-ray powder diffraction. After calcination the powders were ball milled, pressed into pellets and sintered at 950 degrees C, which is lower than the sintered temperature of the conventional solid state method. Using this procedure we achieved relatively high density and very homogeneous BZN ceramics. The dielectric properties of the ceramics were investigated. The results showed the as prepared BZN ceramic possesses relaxation at lower temperatures less than -100 degrees C. The peaks of the dielectric constant in conjunction with the peaks of dielectric loss shift to lower temperatures with frequency decreasing, revealing that the active energy became higher according to Arrhenius law.