X-ray study of swift heavy ion induced interface modifications in multilayer nanostructures

Interfaces play a significant role in determining the properties of multilayer nanostructures: For example, in multilayer X-ray monochromators a controlled magnitude of interface roughness is needed in order to reduce the higher harmonic content. In GMR multilayers like Fe/Cr, Fe/Si, certain amount of interface roughness is needed in order to optimize the GMR. Therefore, it is desirable to modify the interfaces in a controlled manner for tailoring the functional properties of multilayers. Such controlled modification of interfaces can be conveniently achieve using swift heavy ion irradiation. Since the width of the interfacial region ranges from a fraction of a nm to a few nm, it is necessary to use experimental techniques with a depth resolution of 1 nm or better, in order to resolve the structural changes occurring at the interfaces. In the present work some X-ray based techniques have been used to elucidate the interfacial modifications induced by swift heavy ion irradiation, with sub-nanometer depth resolution. High depth resolution of the techniques enables one to study some subtle effects not amenable through other conventional techniques