Synthesis and Characterization of Core-Shell NiFe2O4@MgFe2O4 and ZnFe2O4@MgFe2O4 Nanoferrites

Two magnetic nanocomposites were prepared from spinel ferrite magnetic nanoparticles NiFe2O4 (NF) and ZnFe2O4 (ZF) with MgFe2O4 (MF) using citrate precursor method. The X-ray diffraction confirmed that the structure of all the samples was a single phase of spinel ferrites with space group Fd-3m. The determined lattice parameter (a) is within the expected values of MF, NF, and ZF. The grain size of all the nanocomposites obtained from the high resolution transmission electron microscope images showed that all the samples are in the nanoscale. The vibrating sample magnetometer was used to investigate the magnetic properties. An unexpected value of saturation magnetization (M-S) was obtained for both NF@MF and ZF@MF where NF@MF is less than NF and ZF@MF is higher than of ZF. Self-heating characteristics under an alternating current magnetic field of 9.27 km(-1) and a frequency of 198 kHz were investigated for hyperthermia applications. The results show an upward trend for the samples in the temperature vs. time chart, as a result of increasing in M-S of the samples where the NF@MF has the highest values of SAR.