Effect of divalent ion of strontium substitution on the structural, optical, magnetic and blood compatibility studies in cobalt ferrite

This study investigates the effects of Sr2+ substitution on the structural, morphological, and magnetic properties of magnetic cobalt ferrite (CoFe2O4). Through sol-gel auto-combustion synthesis, Sr2+ was substituted into Co-spinel ferrites (Co1-xSrxFe2O4, where x = 0.0, 0.25, 0.5, 0.75, 1.0). SEM analysis revealed spherical grains with an average size of 54.4 nm. XRD analysis indicated systematic changes in crystallographic parameters and the formation of secondary phases with Sr-substitution. While the crystal size for CoFe2O4 was calculated as 262 nm, this value was determined as 18 nm for Co0.25Sr0.75Fe2O4. FT-IR results suggested increased force constants of octahedral and tetrahedral bonds with higher Sr content, with main vibration bands at 423.6 and 606 cm-1. M-H curves exhibited S-shaped behavior, indicating drastic magnetic property changes with Sr2+ substitution. Coercivity field (Hc), saturation magnetization (M S ), and remanent magnetization (M r ) values ranged from 1447.8-545.4 Oe, 58.8-14 emu g-1, and 36.8-7.6 emu g-1, respectively. Blood compatibility experiments highlighted Co0.75Sr0.25Fe2O4 nanoparticles with significantly low hemolysis rates compared to other concentrations.