Journal of Applied Crystallography

Volume 41, Part 5 (October 2008)

research papers

J. Appl. Cryst. (2008). 41, 831-835 [ doi:10.1107/S002188980802339X ]

Nondestructive characterization of ferrofluids by wide-angle synchrotron light diffraction: crystalline structure and size distribution of colloidal nanoparticles

A. Vorobiev, D. Chernyshov, G. Gordeev and D. Orlova

Abstract: The combination of magnetic and nonmagnetic interactions between the colloidal particles in ferrofluids results in various local inter-particle correlations that, in turn, change the macroscopic properties of the whole system. Therefore, characterization of the particle ensemble is a crucial point, allowing optimization of a ferrofluid for a particular application. Here it is shown how the crystal structure of the particles can be easily obtained in a fast synchrotron light diffraction experiment without any special treatment of the ferrofluid sample. Moreover, from the same diffraction patterns, such important parameters as particle mean size and dispersion are retrieved; these are compared with the corresponding parameters obtained from electron microscopy data. A particular problem of magnetite-maghemite transformation in nanoparticles stabilized by the surfactant shell is pointed out.

Keywords: magnetic/nonmagnetic interactions; colloidal nanoparticles; ferrofluids; wide-angle synchrotron light diffraction.