Bias layers which are formed on underlayers promoting in-plane alignment of the c-axis of cobalt used in magnetoresistive transducers
AssigneeRead-Rite Corporation
InventorsBogdan M. Simion, Yingjian Chen, Mark S. Miller
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Abstract
Bias layers for a magnetoresistive (MR) sensor have an in-plane easy axis of magnetization for providing a longitudinal bias to MR layers. The bias layers include cobalt (Co), and are formed on various underlayers having crystalline structures that encourage an in-plane alignment of the C-axis of that Co. Preferred underlayers include nickel aluminum (NiAl) and magnesium oxide (MgO), and an interlayer containing chromium (Cr) may be interposed between a bias layer and an underlayer.
Claims26
A transducer for sensing magnetic fields, comprising:
- a magnetoresistive device including a plurality of adjoining, substantially parallel layers terminating at first and second ends,
- a seed layer containing a crystalline material adjoining at least one of said ends and having a surface with a lattice constant substantially matching that of a C-axis of cobalt, and
- a magnetic layer containing cobalt disposed over said seed layer and abutting said ends, said magnetic layer having an easy axis of magnetization that is substantially parallel to said interface.
A transducer for sensing magnetic signals, comprising:
- a first magnetic layer formed on a substrate,
- a nonmagnetic layer disposed on said first magnetic layer,
- a magnetoresistive mechanism disposed on said nonmagnetic layer and including a second magnetic layer,
- a third magnetic layer disposed on said nonmagnetic layer and having a coercivity substantially higher than that of said first or second magnetic layers, and
- a plurality of seed layers disposed between said nonmagnetic layer and said third magnetic layer, a first of said seed layers consisting essentially of a first material and a second of said seed layers consisting essentially of a second material, wherein said first and second materials are different.
A transducer for sensing magnetic signals, comprising:
- a first magnetic layer,
- a nonmagnetic layer disposed on said first magnetic layer,
- a magnetoresistive mechanism disposed on said nonmagnetic layer and including a second magnetic layer,
- a seed layer disposed on said nonmagnetic layer and adjoining said magnetoresistive mechanism, and
- a third magnetic layer disposed atop said seed layer, said third magnetic layer containing cobalt and having a coercivity substantially higher than that of said first or second magnetic layers,
- wherein at least one of said nonmagnetic layer and said seed layer contains a material having a crystalline structure promoting formation in said third magnetic layer of an in-plane easy axis of magnetization.
Dependencies are inferred from the claim text.