Origin of colossal dielectric response of CaCu_3Ti_4O_(12) studied by using CaTiO_3/CaCu_3Ti_4O_(12)/CaTiO_3 multilayer thin films

摘要

To elucidate the origin of the colossal dielectric response (CDR) of CaCu_3Ti_4O_(12) (CCTO), multilayer thin films of CCTO interposed in insulating CaTiO_3 (CTO) were synthesized using a pulsed laser deposition technique. The capacitance C of CTO/CCTO/CTO films with different layer thicknesses is measured. After removing the capacitance of CTO by extrapolating C to zero CTO thickness, the real part of dielectric constant of CCTO is estimated to be 329-435, which is much smaller than the reported value for CCTO thin films. This fact indicates that the CDR of CCTO is extrinsic and originates from an internal barrier layer capacitor.