FORC Study of Magnetization Reversal and Interlayer Interactions in Rapidly Quenched Fe/Co-Based Bilayer Ribbons

Study of the interlayer interactions and hysteresis processes was performed for the nano/microcrystalline bilayer ribbon composed of soft magnetic Fe73.5Cu1Nb3Si13.5B9 layer and semihard magnetic Co72.5Si12.5B15 layer. Precursor amorphous ribbons were prepared by modified double-nozzle planar flow casting method. Measurement of the First Order Reversal Curves (FORCs) was utilized for detailed characterization of its magnetic hysteresis behaviour. Calculated switching field distribution (SFD) consists of two distinct peaks, each representing specific magnetic phase. With decreasing reversal field value, SFD peak of the microcrystalline, semihard magnetic Co-based layer is shifted to the higher field values, indicating presence of strong positive exchange interaction. On the other hand, SFD peak of the soft magnetic nanocrystalline Fe-based layer is shifted to lower and even negative field values. Such behaviour was associated with the presence of magnetostatic bias field originating in the semihard magnetic layer.