High dielectric permittivity in Ca1-xBixTi1-xCrxO3 ferroelectric perovskite ceramics

Abstract Polycrystalline structure of Ca1−xBixTi1−xCrxO3 perovskite oxides were prepared by conventional solid state reaction with x = 0.01, 0.03, 0.05, 0.1, 0.3 and 0.5. The crystal structure of the specimens changes with composition. The crystal structure for compositions up to x ≤ 0.1 is similar to that of CaTiO3 with Pnma space group. When 0.1 ≤ x ≤ 0.3, mixed phases in the specimens were observed and it changed to a rhombohedral structure ( R 3 c space group) for x ≥ 0.5. The dielectric constants and dissipation factors were measured at frequencies from 100 to 1 MHz. As a result, the dielectric constants were found to increase with increasing BiCrO3 concentration. For x = 0.3, the dielectric constant at 1 kHz is higher than 600 000 for a sample sintered at 1300 °C for 5 h. The dielectric behaviors of these materials were contributed by orientational and space charge polarizations.

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