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LOWER HC THROUGH SURFACE MODIFICATION

IP.com Disclosure Number: IPCOM000013010D
Original Publication Date: 2000-Apr-01
Included in the Prior Art Database: 2003-Jun-12
Document File: 2 page(s) / 27K

Publishing Venue

IBM

Abstract

A method is described to lower the coercivity of the spin valve freelayer structure. The method is to perform a light ion mill removal (~10A) of the oxide seed layer such as NiO or NiMnO prior to freelayer deposition. The new process reduces the freelayer coercivity from ~7 Oersteds to around 3 Oersteds for spin valve structures.

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LOWER HC THROUGH SURFACE MODIFICATION

   A method is described to lower the coercivity of the spin valve freelayer
structure. The method is to perform a light ion mill removal (~10A) of the oxide
seed layer such as NiO or NiMnO prior to freelayer deposition. The new process
reduces the freelayer coercivity from ~7 Oersteds to around 3 Oersteds for spin
valve structures.

Soft magnetic properties the of spin valve freelayer
structures are critical for the performance of the spin
valve heads. One of these parameters is the coercivity of
the freelayer structure. Various seedlayer types are
utilized to enhance the properties of the spin valve
structures. One type of seedlayer is NiO, or NiMnO, which
is typically 30A thick. It is observed that the
coercivity of the freelayers deposited on these seedlayers
are high when standard deposition steps are used. In the
new method described here, an extra oxide seedlayer is
deposited and this extra part (~10A) is then removed by
ion milling which modifies the oxide surface. Then the
remaining spin valve structure is deposited using the same
processes and layers. The surface modification results in
a large decrease in coercivity. Two spin valve
structures; one processed using the standard method and
the second one processed using the new method are listed
below along with the dR/R and Hc values.

dR/R and Hc of a spin valve structure deposited using
standard process:

NiMnO - 30A dR/R = 7%
CoFe - 7A Hc = 7 Oe.
NiFe - 38A
CoFe - 15A
Cu - 24A
CoFe - 30A
NiMn - 25...