Influence of Cu~(2+) doping on the structure, dielectric and magnetic properties of NiFe_2O_4 prepared by the sol-gel method

摘要

Graphical abstractDisplay OmittedHighlights•The Cu0.2Ni0.8Fe2O4sample sintered at 900 °C showed aMsvalue of 34.61 emu/g.•A phase transition can be realized by changing Cu2+doping concentration.•Both Cu2+and sintering conditions can control the magnetic properties of CNFO.AbstractCuxNi1−xFe2O4powders were prepared by the sol-gel method and the corresponding temperature dependence of microstructure, magnetic and dielectric properties of different CuxNi1−xFe2O4samples have been investigated. Results of XRD and SEM indicate that the Cu2+concentration played an important role in both crystal phase and particle distribution of CuxNi1−xFe2O4. The measurement of magnetic properties shows that both Cu2+doping and sintering temperature could change the saturation magnetization and remanent magnetization in a noticeable manner, and even the magnetic material type. The Cu0.2Ni0.8Fe2O4sample sintered at 900 °C had the largest saturation magnetization (34.61 emu/g), remanent magnetization (17.85 emu/g) and the lowest coercivity (0.17 kOe). The dielectric measurements show strong frequency dependence for all the samples. The peak observed in frequency dependence of dielectric loss measurements shifts to higher frequency with the increasing Cu2+concentration and sintering temperature, indicating a Debye-like dielectric relaxation. All the results indicate that the Cu2+doping has a significant influence on NiFe2O4ferrites.