HREM study of Co/Cu/Co/MnFe spin valves

High resolution electron microscopy (HREM) has been used to investigate the structure of Co(6 nm)/Cu(2.8 nm)/Co(4 nm)/MnFe(12 nm) spin valves so as to correlate the structure with the magnetic properties. The presence of a Ti seed layer enhances the structural quality of the film giving a strong <111> texture and large grain size. It is shown that the <111> texture favours a high exchange bias field. A numerical analysis of the HREM micrographs has been carried out in order to investigate more quantitatively the structure of the interfaces. It has been shown that locally they are diffuse over 2 monolayers in the growth direction.