Synthesis of Micrometric Single Crystalline Magnetite with Superparamagnetic Properties for Biomedical Applications

M. Chirita, M.L. Kiss, A. Ieta, I. Grozescu
State University of New York at Oswego, US

Keywords: superparamagnetic, micrometric single crystal, magnetite

Summary:

There are no reports on the synthesis of single crystalline micrometric magnetite with superparamagnetic behavior. The literature mainly refers to micrometric particles obtained by nanoparticle agglomeration. The major disadvantage of magnetic microparticles composed of clusters of nanoparticles is that saturation magnetization is small compared to single crystalline microparticles. We reported previously the successful synthesis of micrometric magnetite (15-45μm) having single crystalline structure with superparamagnetic behaviour. We present here an optimized route of synthesis for obtaining monodisperse magnetite (10 μm) single crystals. The product was investigated by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, infrared (FT-IR) spectroscopy. The low level of the intensity of the field (3.3 kOe) necessary for reaching saturation (93 emu/g), associated with low levels of remanence (5 emu/g) and coercitivity (25 Oe) indicate superparamagnetic behavior, unusual in particles with micrometric size at room temperature. This property may render the microparticles fit for certain medical applications as they have lower diffusion rates and weaker interactions with the immune system than nanoparticles do.