Tuning of structural, magnetic and heat generation properties of Mg0.4Cu0.6CrxFe2-xO4 spinel ferrites for hyperthermia applications

This study investigates the structural, magnetic and heat generation properties of Mg0.4Cu0.6CrxFe2-xO4 (x = 0, 0.2, 0.5, 1.0) spinel ferrites synthesized using the sol-gel method. The structural parameters were analyzed using X-ray diffraction (XRD) with Rietveld refinement, while Fourier Transform Infrared (FT-IR) spectroscopy confirmed vibrational modes. Magnetic properties were characterized using SQUID magnetometer, including first-order reversal curve (FORC), zero-field-cooled/field-cooled (ZFC/FC) and thermogravimetric (TGA) analyses. The heat generation capability was assessed by measuring the specific absorption rate (SAR) under an alternating magnetic field at 75 kHz. Results indicate that Cr substitution leads to a structural transition from mixed to normal spinel, accompanied by a progressive decrease in saturation magnetization (Ms), coercivity (Hc), and Curie temperature (Tc). Despite the decline in SAR values with increasing Cr content, compositions with x <= 0.5 exhibited sufficient heat generation for hyperthermia applications. The reduction in Tc enhances safety by limiting excessive heating, demonstrating the potential of these materials for controlled hyperthermia treatment.