High Dielectric Permittivity and Maxwell-Wagner Polarization in Magnetic Ni0.5Cu0.3Zn0.2Fe2O4 Ceramics

Nanocrystalline Ni0.5Cu0.3Zn0.2Fe2O4 (NCZFO) powder was fabricated by a modified sol-gel method and then the compacted powder of NCZFO was sintered at 950, 1000, and 1100 C-a similar to for 6 h. The dielectric and electrical properties of sintered samples were investigated as functions of frequency and temperature. All of the NCZFO samples exhibit the high dielectric response behavior and show the Debye-like relaxation, which is attributed to the Maxwell-Wagner polarization and thermally activated mechanisms. The impedance spectroscopy analysis reveals that the NCZFO ceramics are electrically heterogeneous. The sintering temperature has significant influence on the dielectric dispersion behavior of the NCZFO samples, which should be mainly attributed to the large variation of the grain conduction activation energies.