Electron magnetic circular dichroism of epitaxial magnetic thin films at nanoscale

Abstract

Transmission Electron Microscopy (TEM) has been a routine characterization tool for structural and chemical composition analysis of materials by imaging and spectroscopy, respectively. Quantitative magnetic information by electron magnetic circular dichroism technique (EMCD) in a TEM is an innovative idea and new addition based on electron diffraction [1-3]. EMCD is equivalent to X-ray Magnetic Circular Dichroism (XMCD), which is routinely performed in a synchrotron to characterize atom specific orbital and spin magnetic moments in materials [4-6]. Though there are reports on linear dichroism studies in TEM [7] circular dichroism was thought to be possible only with existence of spin-polarized electron source in TEM due to the similarities recognized between the X-ray Absorption Near Edge Structure (XANES) and Energy Loss Near Edge Structures (ELNES) [1,8]. Principle of EMCD is discussed in detail in Section 1.1.1. Schattschneider et al., first theoretically proposed the possibility of a dichroic experiment in TEM in the year 2003 [1], later the experimental feasibility of such proposal named as Electron Magnetic Circular Dichroism (EMCD) was proved in the year 2006 [2].