Compositional imaging of Co/Cr multilayer by high-angle annular dark-field microscopy

Abstract

Magnetic multilayers (ML) have been recently the subject of active research because of their fundamental magnetic behavior (i.e., large magnetoresistance at room temperature and two-dimensional superconductivity etc.) and also because of their potential application as media for perpendicular magnetic recording and information storage. It has been found that the magnetic properties of these ML films strongly depends on their layered structure. Thus it is essential to correlate the growth conditions with the structural, compositional and magnetic properties of the ML films. High resolution electron microscopy (HREM) has proved very useful for providing information about the detailed microstructures of the ML on an atomic scale. But the interpretation of HREM images in terms of chemical modulation across ML films is difficult due to the presence of strong diffraction and phase contrast in HREM images. In this study we have used high-angle annular dark-field (HAADF) microscopy technique to extract compositional information of the e-beam evaporated Co/Cr ML films and to correlate these results with that obtained by HREM.