séminaire exceptionnel du groupe nanomagnétisme)
The control of ultrafast magnetization reversal processes in multilayer nanostructures and magnetic thin films is of major importance for future magnetic memory devices. Experimental access to the magnetization dynamics is then, needed. Time resolved magnetoresistance measurements seem to be an excellent tool to study the magnetization dynamics of individual magnetic nanostructures, like spin valves and magnetic tunnel junctions. Indeed, the relative high giant magnetoresistance and tunneling magnetoresistance of such devices provide easy access to the damping term of the magnetic free layer. However, it is difficult to estimate the influence of adjacent magnetic and non-magnetic layers of the multilayer nanostructure to the magnetization motion of the free layer.
Here, we present the study of the magnetization dynamics of individual microstructured Permalloy thin film devices by time resolved measurements of the anisotropic magnetoresistance (AMR). This technique can be applied to study the magnetization precession and damping of a wide variety of individual ferromagnetic nanolayers.
German Institute of Standards, PTB-Braunschweig