Exchange coupling and magnetic properties of Nd2Fe14B/Co nanocomposite thin films

Abstract The structure, exchange coupling interactions and magnetic properties of magnetron sputtered untextured Nd 2 Fe 14 B/Co thin films with thickness in the range 700–840 nm were studied. Energy products as high as 106 kJ/m 3 (13.3 MG Oe) were obtained for rapidly annealed thin films and are comparable to values obtained in bulk polycrystalline NdFeB alloys containing Co. The exchange coupling interactions between the soft and hard phases were evaluated by recoil demagnetization, irreversible magnetization, and spin-reorientation temperature changes. We find evidence for stronger exchange coupling of grains after a rapid anneal (RA) as compared to a longer time anneal. We suggest that this stronger exchange coupling is due to a uniform nanostructure promoted by the RA.