Microstructural Characterisation of Giant Magnetoresistive Co/Cu Multilayers

Antiferromagnetically-coupled Co/Cu multilayers prepared by magnetron sputtering exhibit pronounced giant magnetoresistance (GMR) effect at room temperature. Using both diffraction and imaging techniques, we studied the in-plane and out-of-plane crystallographic and layering microstructural features of these multilayers. Dominant characteristic features associated with the multilayers, such as lateral and vertical columnar grain orientations as well as layer undulations and regularity, were identified. By deliberately introducing microstructural changes to the materials system using buffer layer and heat treatment, detailed microstructural analysis have provided an insight into the dependence of GMR on microstructures of the multilayers.