Investigation on microstructure and electrical properties of CuAl1-xYxO2 ceramics by electrical impedance spectroscopy

摘要

Y2O3-doped CuAlO2 (CAO) ceramics with delafossite structure were prepared by the solid state oxide reaction method. X-ray diffraction analysis demonstrates that the most of the Y3+ enter into the CAO lattice to occupy Al3+ sites, while the second phase Al5Y3O12 is formed due to the limited solubility of Y2O3 into CAO. The activation energies derived from the temperature depending on bulk conductivity and dielectrically relaxation present a tend to decrease similarly as the Y2O3 is added. Besides, the carrier mobility rises gradually as Y2O3 is added, and turns to sharp augment at the Y2O3 addition reaching to x = 0.04. Hence, at small Y2O3 addition, the emergence of the insulated Al5Y3O12 limits the conductivity; on the other hand, the sharp augment of carrier mobility results from the increase of the conductivity when Y2O3 addition is over x = 0.04. (C) 2015 Elsevier B.V. All rights reserved.