Mimicking very thin particulate coatings by employing a soft-magnetic underlayer

Modern particulate tapes usually consist of a thin layer containing fine metal powder covering a nonmagnetic dummy layer. Because the MP layer is still relatively thick compared with what can be achieved with vacuum deposition techniques the excessive low frequency output can cause saturation in MR heads. Therefore, even thinner MP layers are desirable, but are more difficult to manufacture. Experimental tapes with soft-magnetic underlayers have been prepared with the aim of improving the frequency response. It has proved possible to suppress the long wavelength output by over 4 dB while at the same time improving the frequency response compared with the same thickness of MP on a conventional nonmagnetic underlayer. The incorporation of a soft-magnetic underlayer may therefore be an alternative to manufacturing extremely thin MP layers.