Dielectric relaxation associated with dipolar defect complex in PbZr_xTi_1-xO₃ multilayer

Dielectric behavior of PbZr_0.38Ti_0.62O₃ multilayer with alternating dense and porous PbZr_0.38Ti_0.62O₃ layers was investigated at 420K. Two distinct dielectric relaxation processes were observed in the frequency range from 10² Hz to 10⁶ Hz. The relaxation at lower frequencies is attributed to the space charge polarization. The one at higher frequencies, with a thermal activation energy of 0.49 eV, might originate from the response of singly positive charged defect dipoles V^̈₀-Ti₃₊ to ac electric fields. These dipoles are formed by the doubly ionized oxygen vacancies V₀ and trivalent titanium ions Ti³⁺ as indicated by the results of Auger electron spectrum and electron paramagnetic resonance spectrum.