Microstructure and magnetoelastic properties of FeCo/Ag multilayers

There is growing evidence that in magnetic films of thickness less than 20 nm there can be significant change in the values of magnetic anisotropy constant and magnetoelastic coupling from those of bulk materials. While phenomenological models based on Neel's idea of surface anisotropy may offer a partial explanation, it is vital to develop a more mechanistic understanding. Recently the potential contribution of interface and surface strains to the observed property change has been highlighted. Here we report the field emission gun TEM and electron spectroscopic images of the structure of the interface region between Fe50Co50 and Ag, the local crystallographic texture and the distribution of Ag in magnetostrictive Fe50Co50/Ag multilayers. The results are correlated with the bulk measurements of coercivity and the saturation magnetostriction constant. For the first time it is possible to provide a degree of microstructural interpretation of the magnetic data. (C) 2001 American Institute of Physics.