中國有色金屬學(xué)報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 25 No. 11 November 2015 |
（1. National Laboratory of Solid State Microstructures, Nanjing University, Nanjing 210093, China;
2. Department of Physics, Nanjing University, Nanjing 210093, China;
3. Academy of Space Technology, Nanchang University, Nanchang 330031, China;
4. Department of Applied Physics, School of Science,
Nanjing University of Science and Technology, Nanjing 210094, China）
Abstract:A series of Cu-substituted Ni0.5-xCuxZn0.5Fe2O4 (x=0.12, 0.16, 0.20, 0.24 and 0.28) spinel ferrites were prepared by conventional ceramic method to investigate the effects of Cu compositional variation on the structure and dielectric properties. XRD patterns demonstrate that all the samples are crystallized in single-phase cubic spinel structure and the lattice constant increases with increasing Cu content. White grains observed by SEM are Cu-rich phase. The dielectric constant versus frequency curve displays a normal dielectric behavior of spinel ferrites. While the frequency dependence of dielectric loss tangent is found to be abnormal, exhibiting a peak at certain frequency for all Cu-substituted Ni-Zn ferrites. A maximum of the resistivity is observed at x=0.2 due to the decrease of hopping electrons between Fe2+ and Fe3+ in per unit volume, which is in contrast with the Cu content dependence of dielectric constant and dielectric loss.
Key words: ferrite; Cu ion substitution; dielectric constant; dielectric dispersion; dielectric loss; resistivity
