5th International Conference on Materials Science and Nanotechnology For Next generation (MSNG-2018), Nevşehir, Turkey, 4 - 06 October 2018, pp.95-99
In this study, FeOy magnetic nanoparticles were synthesized by polyol method under N2 atmosphere. X-ray diffraction (XRD) method was used to determine the structural properties of the FeOy MNP. We observed two iron phases that are different oxidation level of iron like FeO and Fe3O4. The less oxidized Fe (FeO) might be taken part as core and the Fe3O4 might cover of the FeO as a shell. The average crystallite size was calculated to be 5.6 nm, which is lower than the critical dimension of the single domain. Scanning electron microscopy (SEM) measurements were performed to obtain information about the morphological characteristics of the synthesized FeO/Fe3O4 nanoparticles. It was observed that the particles were homogeneously dispersed and their sizes were in the range of 3-5 nm, which is consistent with the XRD results. The magnetic properties of the sample were studied by Physical Property Measurement System (PPMS) with a Vibrating Sample Magnetometer (VSM) head. The temperature-dependent magnetization measurements of the FeO/Fe3O4 core/shell like nanoparticles were carried out by sweeping temperature between 5 and 350 K under a magnetic field of 100 Oe in both Zero Field Cooled (ZFC) and Field Cooled (FC) conditions. It has been observed that the FC curve has a systematic decrease in magnetization with increasing temperature. In the ZFC curve, we observed a magnetization peak around 29 K that indicates the blocking temperature. To investigate the magnetic properties of FeOy magnetic nanoparticles more precisely, magnetic hysteresis curves were measured at various temperatures, 10, 30, 50, 100, 150, 200, 250 and 300K, under ± 1 T magnetic field.