Magnetic property enhancement by sputtering magnetically soft films (Co, Fe and Fe65Co35) on PrFeB-type permanent magnet ribbons

This research adopts Co, Fe, and Fe65Co35 (wt.%) as the soft magnetic materials to sputter onto both sides of permanent magnet ribbons with nominal composition of Pr10Fe84.12B5.88 (at.%), attempting to find the possibility of magnetic enhancement by the exchange coupling effect between soft magnetic films and permanent magnet ribbons. Experimental results verified that the magnetic enhancement due to different soft magnetic films onto PrFeB ribbons follows the following sequence: Fe65Co35 > Fe > Co. When Pr10Fe84.12B5.88 ribbons with ∼ 25 μm in thickness is sputtered with 185 nm Fe65Co35, the magnetic energy product, (BH)max, of the laminated materials enhances by 22.64% in comparison with that of the original ribbons. With decreasing temperature, magnetic decoupling between soft magnetic film and hard ribbon occurs even though the coercivity, iHc, of the laminated materials is enhanced.