Magneto-resistive head having a stable response property without longitudinal biasing and method for manufacturing the same

• US 7,733,614 B2
• Filed: 01/24/2007
• Issued: 06/08/2010
• Est. Priority Date: 01/25/2006
• Status: Expired due to Fees

• Current Assignee: Western Digital Technologies Incorporated (Western Digital Corporation)
• Original Assignee: Hitachi Global Storage Technologies Netherlands BV (Western Digital Corporation)
• Inventors: Hoshino, Katsumi, Hoshiya, Hiroyuki, Meguro, Kenichi, Katada, Hiroyuki
• Primary Examiner(s): Cao; Allen T
• Application Number:
  US11/698,251
• Publication Number:
  US 20070188934A1
• Time in Patent Office: 1,231 Days
• Field of Search: 360/324.11, 360/324.12
• US Class Current: 360/324.12
• CPC Class Codes: B82Y 25/00 Nanomagnetism, e.g. magnetoimpedance, anisotropic magnetoresistance, giant magnetoresistance or tunneling magnetoresistance
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• CPC Class Codes: G11B 5/3906 Details related to the use of magnetic thin film layers or to their effects
• CPC Class Codes: G11B 5/399 with intrinsic biasing, e.g. provided by equipotential strips
• CPC Class Codes: H10N 50/01 Manufacture or treatment
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

Embodiments in accordance with the present invention provide a method of manufacturing a magneto-resistive head which can realize high sensitivity and good linear response characteristics with low noise even if a track width becomes narrower. A uniaxial anisotropy unaffected by annealing which is due to the orientation of the crystal grain growth direction, is induced in a magnetic layer. The free magnetic layer has the synthetic antiferromagnetic construction: first magnetic layer/interlayer antiferromagnetic coupling layer/second magnetic layer, the magnitude of the antiferromagnetic coupling is adjusted, and linear response characteristics are obtained even if a longitudinal biasing field applying mechanism is not provided.

Claims

1. A magneto-resistive head, comprising:

a magneto-resistive film including a pinned magnetic layer wherein the magnetization is fixed in the sensor height direction, a free magnetic layer whose magnetization direction varies according to an external magnetic field, and an intermediate layer laminated between said pinned magnetic layer and said free magnetic layer; and

a pair of electrodes for passing a sensing current, wherein;

said free magnetic layer has a laminated structure including a first magnetic layer, an interlayer antiferromagnetic coupling layer and a second magnetic layer,

said first magnetic layer and said second magnetic layer have approximately equal magnetic moments, and

at least one of said first magnetic layer and said second magnetic layer has a uniaxial anisotropy wherein a track width direction is an axis of easy magnetization, due to the orientation of the growth direction of the crystal grains.

2. The magneto-resistive head according to claim 1, wherein, when the external magnetic field is zero, the magnetization of said first magnetic layer and said second magnetic layer have an antiparallel alignment in a substantially parallel direction to the track width direction, the effective net magnetic moment of said free magnetic layer is effectively zero, and the magnetizations of said first magnetic layer and said second magnetic layer shift between a symmetrically antiparallel alignment and a parallel alignment according to a signal magnetic field.

3. The magneto-resistive head according to claim 1, wherein said interlayer antiferromagnetic coupling layer comprises a nonmagnetic layer selected from any of Ru, Re, Cr, Ir, or a film stack including a first nonmagnetic layer selected from any of Ru, Re, Cr, Ir and a second nonmagnetic layer selected from any of Cu, Ag, Au.

4. The magneto-resistive head according to claim 1, wherein said interlayer antiferromagnetic coupling layer is a film stack comprising Ru having a film thickness of 0.7 to 0.9 nm, and Cu having a film thickness of 0.7 nm or less.

5. The magneto-resistive head according to claim 1, wherein said interlayer antiferromagnetic coupling layer comprises an alloy having at least one of the elements Ru, Re, Cr, Ir, Cu as its principal component.