Preparation And Properties Of The High Dielectric Copper Oxide Ceramics

The high-dielectric-constant oxides, as an important class of functionalmaterials, have potential applications in many industrial fields such asmicroelectronics. It is of great significance to understand the highdielectric constant dependence on preparation conditions of the oxides aswell as its physical origin. Compared with the complex oxide CaCu₃Ti₄O₁₂which has been extensively studied in the last ten years, CuO with asimple structure and composition has been paid much less attention,although it demonstrates similar high dielectric properties. In this work,we prepared Cu₂O-doped CuO ceramics, use various experimentaltechniques to characterize CuO ceramics, and investigate the dielectricmechanism in terms of phenomenological models. The main resultsinclude:1. The mechanism of the high dielectric constant of CuO ceramics. TheCuO ceramics samples were prepared by conventional solid state reactionmethod, and temperature-and frequency-dependent dielectric constantswere measured. Based on the assumption of semiconducting grains andinsulating boundaries and the employment of the Maxwell-Wagnermechanism, the Arrhenius relationship and Cole-Cole diagram, we fittedwell with the CuO ceramics low temperature segment dielectrictemperature spectrum, that a semiconductor in the low temperature regionof CuO ceramic grain.2. Cu₂O doped on the prorerties of CuO ceramic. Based on the view thatsemiconductor CuO ceramic grain is caused by copper volatile, variousratios of Cu₂O-doped CuO ceramic samples were prepared byconventional ceramic sintering process. It was found significant change in the dielectric constant of the sample at room temperature （ε_r¹03-105）.And then X-ray diffraction, laser Raman spectrum, scanning electronmicroscopy were used to characterize the ralationship between sample cellvolume and grain size on the doping ratio. IBLC mechanism was used toexplain the cause of the high dielectric constant.