Magnetization-filed (M–H) typical hysteresis curves. a) MFe2O4 (M = Zn, Ni, Cu, and Co) [54], b) CoxZn1-xFe2O4 ferrite [55], c) Li0.25Mn0.5-xCoxFe2.25O4 [56] and d) Co-precipitated CoFe2O4 nanoparticles at various calcination temperatures (600 °C, 800 °C and 1000 °C) [57].