Pyrochlores;
Nanocrystalline Y2Zr2O7;
Particle size;
Impedance spectroscopy;
Microstructure;
AC conductivity;
AC CONDUCTIVITY;
GRAIN-SIZE;
IMPEDANCE SPECTROSCOPY;
ION CONDUCTIVITY;
OXIDE;
BEHAVIOR;
A(2)B(2)O(7);
RELAXATION;
MECHANISM;
MIGRATION;
D O I:
10.1007/s11581-019-03138-7
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
Influence of grain size on electrical properties of nanocrystalline yttrium zirconate (Y2Zr2O7) prepared by hydrothermal method is reported. Appropriate heat treatment has yielded different particle sizes in the range from 2.9 to 30.3 nm. Structural phase analysis by x-ray diffraction, Rietveld analysis and Raman spectroscopy confirmed the cubic pyrochlore structure of YZO. Electrical conductivity and dielectric properties of YZO as a function of temperature for different grain sizes have been studied by impedance spectroscopy. The smallest sized (2.9 nm) YZO exhibited a well-resolved grain and grain boundary conduction because of high fraction of grain boundary volume. Arrhenius type of electrical conduction was shown in YZO, and the conduction species was found to be oxygen vacancies. Activation energy was increasing from 1.14 to 1.32 eV with decreasing grain size. AC conductivity was obeying Jonscher's power law behaviour and non-overlapping small polaron tunnelling model was employed to explain the electrical conduction. Clear dependence of increasing conductivity with increasing grain size was established in YZO. Graphical abstract