Naturally ferrimagnetic magnetite SPM Fe3O4 NPs

Exceptional magnetic properties of magnetite, Fe3O4, and nanoparticles make them one of the most intensively studied inorganic nanomaterials for biomedical applications. We report successful gram-scale syntheses of colloidal Fe3O4 nanoparticles with sizes of 12.9 ± 5.9, 17.9 ± 4.4, and 19.8 ± 3.2 nm via hydrothermal route or controlled coprecipitation in an automated reactor. To investigate structure−property relationships as a function of the synthetic procedure, we used multiple techniques to characterize these nanoparticles' structure, phase composition, and magnetic behavior. For the iron oxide cores of these nanoparticles, powder X-ray diffraction and electron microscopy both confirm single-phase Fe3O4 composition. In addition to the core composition, the magnetic performance of nanoparticles in the 13−20 nm size range can be strongly influenced by the surface properties, which we analyzed with three complementary techniques. With a multidomain magnetic structure, an iron oxide polymorph appealing for various applications because bulk Fe3O4 exhibits a high Curie temperature (TC bulk = 840 K) and the highest saturation magnetization (Ms bulk = 98 emu/g) among iron oxides.1 In nanoparticle (NP) form, the magnetic behavior of Fe3O4 is predominantly determined by the size of the particles. FiM Fe3O4 NPs transition from multi- to single-domain magnetic structure as their size is reduced below 80−90 nm.2 Upon further size reduction to 25−30 nm, Fe3O4 NPs turn into a superparamagnetic (SPM) state at room temperature (RT) as a consequence of the spontaneous flip of their magnetization (M), which is determined by the balance between thermal energy and magnetic anisotropy.2 SPM NPs are desirable for preparing colloidally stable dispersions because larger (≥25−30 nm) FiM NPs exhibit remanence and coercive forces that cause aggregation under a magnetic field. Colloidally stable SPM NPs exhibit a high Ms, good chemical stability, biocompatibility,3, and low toxicity. If you are looking for high quality, high purity and cost-effective Fe3O4, or if you require the latest price of Fe3O4, please feel free to email contact mis-asia.