Electrodeposition of soft, high moment Co-Fe-Ni thin films

The electrodeposition of Co-Fe-Ni films from electrolytes without additives and their magnetic and structural properties in the as-deposited and vacuu m annealed states are reported. Co52Fe26Ni22 alloy films exhibit a saturati on magnetization B-s of 20 kG, coercivity H-c around 1 Oe, resistivity of 2 2 mu Omega cm and saturation magnetostriction of about 10(-6). Crystalline structure from bcc to fcc changes with increasing Ni content; films with be st soft magnetic properties are obtained when bcc and fcc structures coexis t. Varying electrolyte formulation or using pulse plating, the deposition p arameters which yield optimum soft magnetic properties vary, but alloy comp osition and crystalline structure of optimum films are unchanged. dc plated films exhibit Ni enrichment at the interface in a region of about 1 mu m t hickness. Easy axis annealing in a vacuum of 10(-7) Torr at 200-280 degrees C for 30 min decreases H-c and slightly decreases the anisotropy field. An nealing, however, does not change B-s, crystalline structure or lattice par ameters, demonstrating stability of the film structure when subjected to ty pical device processing temperature cycles. (C) 2000 American Institute of Physics. [S0021-8979(00)72908-2].