In situ TEM observation of magnetic materials.

Magnetic nanostructures and thin films display novel magnetization reversal behavior as a function of size and shape, which makes them appropriate for a range of technological applications. The spatial resolution of in situ transmission electron microscopy techniques such as Lorentz TEM (LTEM) and off-axis electron holography are well suited to analysis of the magnetic domain structure and magnetization behavior of these magnetic nanostructures and thin films. In this article the various techniques that are applicable are described, including the qualitative LTEM imaging modes and the differential phase contrast technique. In addition, quantitative methods for mapping the magnetic induction via phase reconstruction are discussed. In each case the advantages and limitations are presented. Application of the techniques to various types of magnetic structures is then presented, and the article ends with a short summary and a discussion of future developments in this field. (c) 2009 Wiley-Liss, Inc.