Nano-magnetic materials have a variety of potential applications. For example, they can be used in high density data storage and in biomedical research and clinical diagnosis. Fundamentally, it is important to understand that the nano particle size is not always the crystallite size. One particle may contain several differently oriented crystallites or domains.
In the figures below, we demonstrate the analysis of both the crystallite size and nano particle size of magnetic FePt materials. XRD is sensitive to the crystal structure; hence it is suitable for the crystallite size analysis. On the other hand, SAXS is not sensitive to the crystal structure, but the particle size. Both the XRD and SAXS analyses were performed on the SmartLab multipurpose diffractometer. The XRD and the crystallite size results are shown in Figure 1.
The SAXS measurement and fitting results are shown in the left panel of figure 2. The resulting particle size distribution is shown in the right panel of Figure 2.
For the particular sample analyzed here, the crystallite size is identical to the particle size, 2.9 nm. This indicates that each particles contains just a single domain.