Patent US4049197A successfully refreshed from Google Patents.
US5609971A
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Thin film magnetic head
Assignee: OL Security LLC
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Filing: 1994-06-24
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Granted: 1997-03-11
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Expires: 2014-06-24
Abstract
Abstract A thin film magnetic head comprising a lower magnetic core layer 9 and an upper magnetic core layer 12 formed over the core layer 9 with a coil layer 10, a gap spacer layer 11 and an insulating layer provided therebetween, the core layers 9 and 12 each having a core tip region c between a core tip a and a portion b increasing in core width. The core layers 9 and 12 are each formed by a magnetic thin film of NiFe having a positive magnetostriction constant of not greater than 1×10 -6 in absolute value and containing 17.5 to 19.5 wt. % of Fe.
Inventors
- 👤 Naoto Matono
- 👤 Hitoshi Noguchi
- 👤 Tomomi Yamamoto
- 👤 Shinji Kobayashi
- 👤 Masahiro Nakata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 09:41
CPC Classifications
G; G11; G11B; G11B5/00; G11B5/127; G11B5/147; G11B5/1475; G11B5/31; G11B5/3109; G11B5/3116; G11B5/33; G11B5/39; G11B5/3903; G11B5/3967; Y; Y10; Y10S; Y10S428/00; Y10S428/90; Y10T; Y10T428/00; Y10T428/11; Y10T428/1171; Y10T428/12; Y10T428/12493; Y10T428/12771; Y10T428/12861; Y10T428/12937
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
110 words
A thin film magnetic head comprising a lower magnetic core layer and an upper magnetic core layer formed over the lower core layer with a coil layer, a gap spacer layer and an insulating layer provided therebetween, at least one of the lower magnetic core layer and the upper magnetic core layer having a core tip region between a core tip and a portion increasing in core width, the core tip region having a track width of not greater than 6 μm, the magnetic core layer with the core tip region being formed by a CoZr amorphous magnetic thin film having an anisotropic magnetic field of at least 10 Oe.
Claim 2
Dependent Claim
110 words
A thin film magnetic head comprising a lower magnetic core layer and an upper magnetic core layer formed over the lower core layer with a coil layer, a gap spacer layer and an insulating layer provided therebetween, at least one of the lower magnetic core layer and the upper magnetic core layer having a core tip region between a core tip and a portion increasing in core width, the core tip region having a track width of not greater than 6 μm, the magnetic core layer with the core tip region being formed by a CoZr amorphous magnetic thin film having an anisotropic magnetic field of at least 10 Oe.
Claim 3
Dependent Claim
24 words
A thin film magnetic head as defined in claim 1 wherein the anisotropic magnetic field is in the range of 13 to 20 Oe.
Claim 4
Dependent Claim
20 words
A thin film magnetic head as defined in claim 2 wherein the core tip region has a 180° domain wall.
Claim 5
Dependent Claim
124 words
A thin film magnetic head having an inductive head portion for recording use only, the inductive head portion comprising a lower magnetic core layer and an upper magnetic core layer formed over the lower core layer with a coil layer, a gap spacer layer and an insulating layer provided therebetween, at least one of the lower magnetic core layer and the upper magnetic core layer having at least a core tip region between a core tip and a portion increasing in core width, the core tip region having a track width of not greater than 6 μm, the magnetic core layer with the core tip region being formed by CoZr amorphous magnetic thin film having an anisotropic magnetic field of at least 10 Oe.
Claim 6
Dependent Claim
124 words
A thin film magnetic head having an inductive head portion for recording use only, the inductive head portion comprising a lower magnetic core layer and an upper magnetic core layer formed over the lower core layer with a coil layer, a gap spacer layer and an insulating layer provided therebetween, at least one of the lower magnetic core layer and the upper magnetic core layer having at least a core tip region between a core tip and a portion increasing in core width, the core tip region having a track width of not greater than 6 μm, the magnetic core layer with the core tip region being formed by CoZr amorphous magnetic thin film having an anisotropic magnetic field of at least 10 Oe.
Claim 7
Dependent Claim
26 words
A thin film magnetic head as defined in claim 4 wherein a magnetoresistive head portion for reproduction use only is formed on the inductive head portion.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2000-03-10 | 2000-09-09 | 2001-03-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-03-10 | 2004-09-09 | 2005-03-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-03-10 | 2008-09-09 | 2009-03-11 | $7700.00 | Window Closed / Lapsed |