Processing, structural and electric properties of CaCu3Ti4O12 (CCTO) doped with GeO2. (4th December 2009)

• Record Type: Journal Article
• Authors: Amaral, F.; Silva, C.C.; Valente, M.A.; Costa, L.C.
• Is Part Of: International journal of nanomanufacturing. Volume 5:Number 1/2(2010)
• Page Start: 25
• Page End: 37
• Publication Date: 2009-12-04
• Subjects: giant dielectric constant -- dielectric relaxation -- perovskite structure -- ceramics -- nanocrystals -- nanomaterials -- nanotechnology -- CaCu3Ti4O12 -- CCTO; Nanostructured materials industry -- Periodicals; Nanotechnology -- Periodicals; 620.505
• Languages: English
• ISSNs: 1746-9392

Abstract

The CaCu3Ti4O12 (CCTO) is a material with a giant dielectric constant at room temperature and good temperature stability over a wide temperature and frequency ranges. The preparation method and doping has a great influence on the microstructure and dielectric properties of this material. In this work, the samples were prepared starting from CuO, TiO2, CaCO3 and GeO2 in appropriate amounts to obtain CaCu3Ti4−xGexO12 with x = 0 and x = 0.1. Three processing methods were used: solid state technique, high energy ball milling and microwave processing in a domestic microwave oven. The samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and dielectric measurements. The presence of nanocrystals was confirmed by XRD. The composition of the grains and grain boundaries has been determined by SEM with energy dispersive X-ray spectrometry mapping. AC impedance spectroscopy measurements in the 102-107 Hz frequency range, at room temperature, have been performed. The obtained results are discussed and correlated with the preparation method.