TEM and electron holography analyses of granular and thin layered Cu–Co magnetic materials

The paper shows the examples of application of transmission electron microscopy (TEM) techniques for characterization of two types of copper–cobalt magnetic nanomaterials: Cu-10 wt% Co granular giant magnetoresistance (GMR) thin ribbons and thin nanocrystalline Co films deposited on Cu substrate. Quantitative TEM microstructural analyses were used for determination of Co particle size distributions in GMR ribbons. It was demonstrated that the relative resistivity depends on the mean diameter of the cobalt nanoparticles. For nanocrystalline thin Co layers, off-axis electron holography was used to investigate their magnetic structure. The mean in-plane component of the magnetic field in cobalt was calculated from the phase gradient.