Particle sizing of magnetite-based magnetic fluid using atomic force microscopy: A comparative study with electron microscopy and birefringence

Atomic force microscopy (AFM), transmission electron microscopy (TEM), and static magnetic birefringence (SMB) were used to unfold the particle size p olydispersity profile of a magnetite-based magnetic fluid sample. The data obtained from different techniques were curve fitted using the lognormal di stribution function, from which the mean particle diameter (D-m) and the st andard deviation (sigma) were obtained. In comparison to the TEM data, the AFM data show a reduction of D-m (about 20%) and an increase of sigma (abou t 15%). In contrast, close agreement between the TEM and SMB data was found . (C) 2000 American Institute of Physics. [S0003-6951(00)02538-9].