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Laminated Film Medium with Different Magnetic Layers

IP.com Disclosure Number: IPCOM000122758D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 1 page(s) / 41K

Publishing Venue

IBM

Related People

Ahlert, RH: AUTHOR [+3]

Abstract

Disclosed is a film disk structure for magnetic recording applications using a laminated magnetic structure comprising magnetic layers of different alloys and magnetic properties. Such structures provide a novel means to vary coercivity, modify the squareness of the hysteresis loop or adjust the remnant moment for a given total magnetic film thickness. It is found, for example, that laminated structures of CoPt and CoPtCr layers separated by thin Cr spacer layers exhibit performance characteristics combining the low-noise behavior of CoPtCr with the increased moment of CoPt. Thus, the use of mixed multilayers may be used to tailor performance in films with high remnant moment - thickness product, for inductive head applications.

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Laminated Film Medium with Different Magnetic Layers

      Disclosed is a film disk structure for magnetic recording
applications using a laminated magnetic structure comprising magnetic
layers of different alloys and magnetic properties. Such structures
provide a novel means to vary coercivity, modify the squareness of
the hysteresis loop or adjust the remnant moment for a given total
magnetic film thickness. It is found, for example, that laminated
structures of CoPt and CoPtCr layers separated by thin Cr spacer
layers exhibit performance characteristics combining the low-noise
behavior of CoPtCr with the increased moment of CoPt.  Thus, the use
of mixed multilayers may be used to tailor performance in films with
high remnant moment - thickness product, for inductive head
applications.

      A requirement for these structures is that the non-magnetic
spacer layer be thick enough to provide de-coupling of the magnetic
layers.  In practice, it is found that a chromium thickness of 10
Angstroms is sufficient.  The resulting hysteresis loops of these
structures exhibit discrete switching characteristics depending on
the number and type of magnetic layers; however, no adverse effect on
the recording performance was observed as a result of the
discontinuous hysteresis properties.

      Disclosed anonymously.