FMR Studies of Metallic Magnetic Thin Films in Layered Structures

We will present and discuss, in this paper, results of FMR studies performed on metallic magnetic thin films. Specifically, the thin films studied correspond to metallic systems where a metallic ferromagnetic layer is in contact with a paramagnetic normal metal in a layered structure sample geometry. Such a layered structure geometry is well appropriate, with respect to the magnetic properties studied, for the investigation of various physical phenomena occuring at different length scales. Different physical questions have been addressed in our FMR studies and they will be successively discussed in the present report according to the following classification where the physical phenomena studied are ranked in increasing order of complexity: (i) in ultrathin layers of the magnetic material interface effects are expected to be revealed, in particular, in the magnetic anisotro-py. One of the goals of our experimental investigation is thus to extract an information on the specific interface-induced magnetic anisotropy, characteristic of the interface studied. This is achieved by studying single magnetic layers, either “ultrathin” or “thick”, (ii)we are also concerned more generally in such layered structure metallic systems with a systematic study of the magnetic interfacial coupling (magnetic proximity effects) between a thin metallic ferromagnetic film and a normal metal. (iii)finally we raise the problem of the nature of inter-magnetic layer coupling in metallic magnetic multilayer structures.