A similar behavior was observed for the Mg0.2Ca0.8Fe2O4 ferrites synthesized in this work.
Saturation magnetization increased from 30.6 to 38.9 emu/g as the heat treatment temperature was increased from 573 to 873 K. This fact can be explained taking into account that at higher temperatures, the particle size increases and the microstructure becomes well-crystallized [22].