Development and characterization of magnetic nanoparticles Co-=SUB=-1-x-=/SUB=-Zn-=SUB=-x-=/SUB=-Fe-=SUB=-2-=/SUB=-O-=SUB=-4-=/SUB=- (0≤ x≤0.6) for biomedical applications

Abstract

The results of studies of the properties of co-deposition of magnetic nanoparticles (MNPs) of Co1-xZnxFe2O4 spinel ferrites synthesized (at x=0.0; 0.1; 0.2; 0.4; 0.6) in order to synthesize magnetic particles for biomedical applications. X-ray diffraction (XRD), raman spectra, magnetic measurements and Mossbauer spectroscopy (MS) were used to study the Co1-xZnxFe2O4 MNPs. It was found that the synthesized MNPs CoxZn1-xFe2O4 are single-phase. According to the results of XRD measurements, it was found that the average sizes of crystallites are 13 nm for CoFe2O4 (x=0) and, with an increase in the Zn concentration, they decrease to 7 nm for Co1-xZnxFe2O4 (x=0.6), which is consistent with the Mossbauer data, which showed that the sizes of crystallites vary from 14 to 8 nm. In the raman spectra of the Co1-xZnxFe2O4 MNPs in the region of ~620 cm-1, splitting of the A1g, line is observed, indicating that the studied particles have an inverse spinel structure. The change in the ratio between intensities of A1g (1) and A1g (2) peaks is indicative of a significant redistribution of Co2+ and Fe3+ cations between tetrahedral andoctahedral positions in Co1-xZnxFe2O4 MNPs as the quantity of Zn increases, which is confirmed by the Mossbauer data. It is found that small sizes of MNPs result in a strengthening of the effects of size and an effect of surface on the magnetic structure of the surface layer. The MS analysis has shown that there is a layer on the MNP surface, the magnetic structure of which is different from from the structure of the crystallite volume. With increase in the quantity of Zn ions thickness of this layer increases and at x=0.6 the particle becomes completely paramagnetic. Mossbauer studies have shown that Co0.8Zn0.2Fe2O4 (x=0.2) particles are inthe superparamagnetic state and theirmagnetic blocking temperature is ~315 K, which is the most acceptable for the treatment of cancer by the magnetic hyperthermia method. Keywords: CoxMn1-xFe2O4, spinel ferrites, magnetic structure, superparamagnetism, Mossbauer spectroscopy, materials for biomedicine.