The effect of the annealing temperature on the microstructural, magnetic, and spin-dynamical properties of Mn-Mg-Cu-Zn ferrites

The effect of the annealing temperature on the structural and magnetic properties of Mn0.15Mg0.15Cu0.2Zn0.5-Fe2O4 ferrite nanoparticles was investigated. All samples were carefully characterized using different techniques. The structural results showed that the ferrite was annealed at temperatures above 750 degrees C, and its structure was a combination of cubic spinel and hematite phases. Moreover, the XPS analysis showed that the valence state of the surface-metal ions and the surface-oxygen species played an important role in the structural and magnetic changes of this ferrite, so the increase in the hematite phase with the annealing temperature can be explained by the evaporation of the zinc content and the formation of a magnesium-metal state. The imaginary susceptibility as a function of the temperature of the samples shows a broad peak at high temperatures related to the blocking temperature of the interacting superparamagnetic nanoparticles and a second sharp peak related to the insulating spin-glass temperature.

Automated summary

The annealing temperature significantly affects the structural and magnetic properties of Mn0.15Mg0.15Cu0.2Zn0.5-Fe2O4 ferrite nanoparticles. The structural results showed a combination of cubic spinel and hematite phases at temperatures above 750 degrees C. XPS analysis revealed the importance of the valence state of surface-metal ions and surface-oxygen species in these changes.