LARGE BARKHAUSEN DISCONTINUITY OF CO-FE-SI-B AMORPHOUS FILMS SPUTTERED ON POLYMER SUBSTRATE

Co-Fe-Si-B films have been prepared using a roll coater and DC magnetr on sputtering system onto a polyethylene terephthalate substrate. This thin film exhibited an excellent uniaxial anisotropy introduced by an asymmetric thermal shrinkage of the substrate. Reversal with a single layer Barkhausen pulse has been observed in a thin film structure 1mm by 50mm by 0.65 mu m. Closure domains have been clearly identified at the film ends. The threshold for the reversal is the coercive force. The reason for reversal with a single Barkhausen jump is that the long narrow film geometry has essentially zero demagnetizing field over mo st of the film. Once the walls start to move through the center portio n of the film, there is nothing to stop them so the reversal proceeds with a single large Barkhausen pulse.