Chapter 9: Determining the Magnetic Anisotropy at the Nanoscale by Means of X-ray Magnetic-sensitive and Element-selective Microscopy Methods Check Access

Magnetic nanoparticles can nowadays be found in a myriad of applications as diverse as data storage, molecular imaging, wastewater treatment, tissue engineering, or targeted cancer therapies. Despite their increasing importance, their individual magnetic properties are unknown to a large extent, given the difficulty in obtaining magnetic information with nanometric resolution. Indeed, the implementation of magnetic nanoparticles relies on average values obtained by measuring a plethora of dissimilar entities. In this chapter, we explain how magnetic-sensitive microscopy techniques, available at large-scale synchrotron radiation facilities, in combination with theoretical simulations, can contribute to overcoming this limitation. As a case study, we present two examples making use of X-ray photoemission electron microscopy (XPEEM) and scanning transmission X-ray microscopy (STXM) to obtain quantitative information concerning the magnetic anisotropy of individual magnetic nanoparticles biosynthesized by magnetotactic bacteria. The method presented here may be considered general and applicable to any magnetic system at the nanoscale.