High Dielectric Permittivity and Low Transition Temperature of (1 – x)CaTiO3– xFeTiO3 Inorganic Composites (x = 0.0 to 1.0)

In this paper, we improved the dielectric properties of CaTiO3 by adding ilmenite (FeTiO3). For this, we synthesized (1 – x)CaTiO3 – xFeTiO3 for a large composition from x = 0.0 to 1.0 by using the conventionnel solid-state method. Several characterization techniques were used to study the structural and dielectric properties of these composites. Following the X-ray diffraction results we confirmed that pure CaTiO3 (CT) and FeTiO3 (FT) crystalize in orthorhombic phase with Pbnm and Pmmm space groups, respectively; while for x = 0.1 to 0.9 we have succeeded to synthesize these composites with the phase mixture of two Pbnm and Pmmm orthorhombic phase, without presence of any secondary phase. The Raman spectroscopy results confirm these phases mixture (for x = 0.1 to 0.9) and the pure CT and FT bands formation. The SEM micrographs of CT sample show spherical grains while with the increase of FT content, the elongated grain shape appeared. On the other hand, the grain size is minimal at x = 0.2 and 0.5 of x content and the density is improved in these samples. The dielectric measurements of these composites were investigated as function of frequency (from 20 Hz to 2 MHz) and temperature (from room temperature to 550°C). The results confirmed the stability in dielectric permittivity of CT at this range of temperature, while with adding FT we obtained a phase transition which shifted to the lower temperature with the increase of x content. In addition, the dielectric permittivity increased with the increase of x rate and reached a colossal value for the sample at x = 0.5, which confirmed the improvement of dielectric properties of CT. The frequency dependence of dielectric permittivity showed a ferroelectric behavior for all the composites.