The influence of grain size on the magnetic properties of Fe3O4 nanocrystals synthesized by solvothermal method

The peculiar magnetic properties of superparamagnetic iron oxide nanoparticles (SIONs) have spurred great interest in their potential application in enhancing medical images and drug delivery. Currently hindering the application of nanomagnetic particles in these fields is due to SIONs nonuniform size distribution, agglomeration, non-crystallinity, and low magnetic moment. In this paper, magnetic nanocrystals of different sizes and morphologies were prepared by the solvothermal method, which utilized an n-hexane-surfactant system with Fe(acac)(3) and iron-powder precursors. The crystalline structure and particle size of grown SIONs are characterized by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). HRTEM showed that the SIONs were approximately 5.6-6.8 nm in size with no agglomeration and a uniform distribution. Within the reaction time, HRTEM also confirmed that the shape and nanocrystals of SIONs had changed from an irregular crystal shape to triangles and quadrilaterals, and finally to hexagonal nanoparticles. According to the test results of the magnetic properties test and the literature, the material that has been synthesized is a superparamagnetic material. And the maximum saturation magnetization was 62.65 emu/g, which is reported among the largest magnetic properties of SIONs at a size of 6.8 nm. Superparamagnetic Fe3O4 nanoparticals with different size and morphology were prepared by solvothermal method in N-hexane-surfactant system with the precursors of Fe(acac)(3) and iron powder. With the increasing reaction time and under the regulation of the surfactant molecules, the morphology and nanocrystals of SIONs have initially changed from the irregular crystal to triangles and quadrilaterals shape, and finally to the hexagonal nanoparticles.

Automated summary

The study successfully prepared superparamagnetic iron oxide nanoparticles with different sizes and morphologies, and verified their magnetic properties through experiments. During the reaction process, the shape and crystal structure of the nanoparticles changed significantly, ultimately forming hexagonal nanoparticles.