CoxFe3−xO4 (x = 1, 1.2, 1.4, 1.6 and 1.8) were synthesized with solvothermal route.
Nanoparticle sizes are less than 10 nm.
Surface effects and interparticle interactions were found for x = 1.6 and 1.8.
Surface effects have been deduced by Bloch's law fitting.
Interparticle interactions have been deduced by Kneller's law fitting.