MAGNETIC CLUSTERS, INTERGRANULAR EXCHANGE INTERACTION AND THEIR MICROSTRUCTURAL BASIS IN THIN-FILM LONGITUDINAL MEDIA

We have experimentally examined the micromagnetic structures in CoCrTa /Cr films deposited onto NiP/Al substrates at 25, 100, 150, 200 and 25 0 degrees C. We prepared all the films in an acerased magnetic state, The Lorentz transmission electron micrascopy images demonstrate a mono tonic decrease of magnetic cluster size with increase of deposition te mperature and the magnetic force microscopy results show a decrease of image contrast, This indicates a decrease of intergranular exchange c oupling with increase of deposition temperature. Nanoprobe energy disp ersive spectroscopy (EDS) reveals an increase of Cr segregation at CoC rTa grain boundaries with increase of deposition temperature, The corr elation of micromagnetic and microcompositional observations supports that er segregation at grain boundaries is responsible for decoupling CoCrTa grains, Our nanoprobe EDS results also indicate that the Cr dif fuses to the grain boundaries from the inside of the CoCrTa grains as opposed to a diffusion process involving the Cr underlayer.