Soft Magnetic Properties of Electrodeposited CoNiFe Films

The soft magnetic properties of electrodeposited CoNiFe films were studied. Films composed of 30 to 50 wt% Co, 23 to 35 wt% Ni and 25 to 35 wt% Fe alloy with a high saturation flux density of more than 1.5 T exhibit low coercivities under 0.2 Oe. Film composed of 40 Co-30 Ni-30 Fe alloy, consisting primarily of an fcc phase with some bec phase material and created by annealing at 300°C, has excellent soft magnetic properties (H
_c
=0.06 Oe, μ=3200, B
s
=1.8 T). This bcc phase makes an appearance during the first stage of crystallization at 287°C. The structure is thermally unstable, and is due to a special feature of electrodeposition. During the annealing, H
₂
O, H
₂
and CO
₂
were released from the film, but the patterns of generation of these gases bear little relation to the DSC pattern.