Patent ID: 7135103

Claim:
A method for preparing an electroplated soft magnetic thin film of a cobalt-iron alloy which consists essentially of 30 to 50 at % of cobalt and 50 to 70 at % of iron and has a saturation flux density of at least 2.3 T, comprising the steps of: furnishing a plating tank including a cathode compartment and an anode compartment which are separated by a diaphragm or salt bridge so as to permit charge transfer, but inhibit penetration of iron ions, the cathode compartment receiving a plating solution containing cobalt ions and divalent iron ions, and the anode compartment receiving an electrolyte solution, immersing a work piece in the plating solution, immersing an anode in the electrolyte solution, effecting electroplating by conducting pulse current across the anode and the workpiece with a pulse current density of 75 to 300 mA/cm 2 , a pulse duration of 0.01 to 0.1 second, and a duty ratio of 0.01 to 0.5 to form a film on the work piece, and heat treating the film at a temperature of 100 to 550° C.