Barrier Layer Capacitors Based on Calcium-Copper-Titanate

Calcium-Copper-Titanate (CCTO) is one of a class of non-ferroelectric, highly tilted Perovskite-structured oxides. Theoretical values of permittivity for these materials are low and fairly typical for non-ferroelectrics, yet these materials received considerable attention when reports of extremely high permittivity (in excess of 10,000) emerged, with one study on CCTO published in Science that attempted to assign the unusual behaviour to an as yet unknown exotic polarisation mechanism. This thesis proves that the high permittivity is actually extrinsic in origin and originates from a barrier layer capacitance effect; the measured values for intrinsic permittivity for CCTO and related ceramics was found to be low and comparable to theoretical values.