Transducer with improved inductive coupling

• US 5,311,386 A
• Filed: 06/26/1991
• Issued: 05/10/1994
• Est. Priority Date: 06/02/1989
• Status: Expired due to Fees

• Current Assignee: Matsushita-Kotobuki Electronics Industries, Ltd.
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Mallary, Michael I.
• Primary Examiner(s): Levy, Stuart S.
• Assistant Examiner(s): EVANS, JEFFERSON A
• Application Number:
  US07/721,233
• Time in Patent Office: 1,049 Days
• Field of Search: 360/119, 360/123, 360/125, 360/126, 428/336
• US Class Current: 360/125.33
• CPC Class Codes: G11B 5/127 Structure or manufacture of heads, e.g. inductive
• CPC Class Codes: G11B 5/17 Construction or disposition of windings
• CPC Class Codes: G11B 5/31 using thin films G11B5/1274, G11B5/1278, G11B5/1874, G11B5/1875, G11B5/33, G11B5/49 take precedence; magnetic thin film structures H01F10/00
• CPC Class Codes: G11B 5/3113 for improving the magnetic domain structure or avoiding the formation or displacement of undesirable magnetic domains
• CPC Class Codes: G11B 5/313 Disposition of layers
• CPC Class Codes: G11B 5/3163 Fabrication methods or processes specially adapted for a particular head structure, e.g. using base layers for electroplating, using functional layers for masking, using energy or particle beams for shaping the structure or modifying the properties of the basic layers
• CPC Class Codes: Y10T 29/49034 Treating to affect magnetic properties
• CPC Class Codes: Y10T 29/49055 with bond/laminating preformed parts, at least two magnetic

Abstract

A thin film magnetic transducer is formed in a plurality of layers and comprises a yoke with at least one arm having segments respectively lying in separate the layers and connected through a transition layer, and one or more coils; the coil (or coils) and the yoke are intertwined to provide more than two flux interactions therebetween. In one aspect, the segments of the arm are oriented obliquely to each other and have easy axes of magnetization respectively transverse to the directions of flux conduction through the segments, and the segments are joined together so that flux can pass between them without flowing parallel to the easy axis of any of the segments.

Claims

1. A thin film magnetic transducer formed in a plurality of layers and comprising

a yoke that includes at least one arm having segments respectively lying in separate said layers and connected through a transition layer, at least one of said segments being disposed generally along a longitudinal axis of said transducer and having an easy axis of magnetization oriented transverse to a direction of flux conduction through said segment and at an oblique angle to said longitudinal axis, and

a coil having at least one turn, said yoke and said coil being intertwined to provide more than two flux interactions between said yoke and said at least one turn.

2. The transducer of claim 1 wherein each one of said segments is disposed generally along said longitudinal axis and has an easy axis of magnetization oriented transverse to a direction of flux conduction through said segment and at an oblique angle with respect to said longitudinal axis, whereby said yoke conducts flux predominantly by rotation rather than by wall motion.

3. The transducer of claim 2 wherein each one of said segments is disposed at an oblique angle with respect to said longitudinal axis and has said easy axis oriented generally perpendicular to said segment.

4. The transducer of claim 1 wherein said segments are connected by a via that passes through said transition layer.

5. The transducer of claim 1 wherein said coil lies at least in part in said transition layer.

6. The transducer of claim 1 wherein said yoke further comprises a second arm having segments respectively lying in separate said layers and connected through said transition layer, said second arm being connected to said one arm to form a flux path with a storage medium.

7. The transducer of claim 6 wherein a segment of said second arm is connected to a segment of said one arm through said transition layer.

8. The transducer of claim 6 wherein each one of said segments of said second arm is disposed generally along said longitudinal axis and has an easy axis of magnetization oriented transverse to a direction of flux conduction through said segment and at an oblique angle with respect to said longitudinal axis, whereby said second arm conducts flux predominantly by rotation rather than by wall motion.

9. The transducer of claim 8 wherein each one of said segments of said second arm is disposed at an oblique angle with respect to said longitudinal axis and has said easy axis oriented generally perpendicular to said segment.

10. The transducer of claim 1 wherein said yoke includes a single said arm constructed to form a flux path with a storage medium.

11. The transducer of claim 10 wherein said arm includes a tip arranged to be disposed adjacent to a storage medium and a region constructed to cause flux in said arm to be radiated from said arm by said region.

12. The transducer of claim 1 wherein said coil includes multiple turns, said yoke and said coil being intertwined to provide more than two flux interactions between said yoke and each one of said turns.

13. The transducer of claim 1 wherein said yoke comprises an alloy of nickel-iron-cobalt.

29. The transducer of claim 1 wherein said at least one segment is disposed at an oblique angle with respect to said longitudinal axis and said easy axis is oriented generally perpendicular to said segment.

30. The transducer of claim 1 wherein the easy axes of magnetization of said at least two segments are oriented obliquely to each other.

14. A thin film magnetic transducer comprising

a yoke including at least one arm having at least one easy axis of magnetization, and

a coil having at least one turn, said yoke and said coil being intertwined to provide more than two flux interactions between said yoke and said at least one turn,

said arm having a plurality of elongated segments oriented obliquely to each other and having easy axes of magnetization respectively transverse to the directions of flux conduction through said segments, said segments being joined together to direct flux through said coil, the easy axis of magnetization of at least two of said segments that are joined together being oriented in different directions.

15. The transducer of claim 14 wherein said transducer is formed in a plurality of thin film layers, and said oblique segments lie in separate said layers, said segments being joined together through a transition layer disposed between said layers.

16. The transducer of claim 15 wherein said coil is disposed at least in part in said transition layer.

17. The transducer of claim 14 wherein said yoke further includes a second arm having at least one easy axis of magnetization, said second arm having elongated segments oriented obliquely to each other and easy axes of magnetization respectively transverse to the directions of flux conduction through said segments, said segments of said second arm being joined together and a segment of said second arm being connected to a segment of said one arm to direct flux through said coil.

18. The transducer of claim 17 wherein said transducer is formed in a plurality of thin film layers, and said oblique segments of said second arm lie in separate said layers, said segments being joined together through an intermediate portion extending between said layers.

19. The transducer of claim 17 wherein said transducer is formed in a plurality of thin film layers with said oblique segments of said second arm lying in separate said layers and being connected together through a transition layer, said coil lying at least in part in said transition layer.

20. The transducer of claim 17 wherein the easy axis of each one of said segments of said second arm is perpendicular to a direction along which said segment generally extends.

21. The transducer of claim 17 wherein said transducer is formed in a plurality of thin film layers with said oblique segments of each one of said arms lying in separate said layers, the segments that are disposed in a first one of said layers extending generally in a first direction and having easy axes of magnetization perpendicular to said first direction, and the segments that are disposed in a second one of said layers extending generally in a second direction oblique to the first direction and having easy axes of magnetization perpendicular to said second direction.

22. The transducer of claim 17 wherein said segments are intertwined with said coil to provide four flux interactions between said at least one turn of said coil and said yoke.

23. The transducer of claim 14 wherein said yoke comprises a single said arm.

24. The transducer of claim 23 wherein said yoke and said coil are intertwined to provide three flux interactions between said yoke and said at least one turn of said coil.

25. The transducer of claim 14 wherein each one of said segments has an easy axis of magnetization oriented at an oblique angle with respect to a longitudinal axis of said transducer.

26. The transducer of claim 14 wherein the easy axes of magnetization of at least one of said segments is oriented at an oblique angle relative to the easy axis of another one of said segments.

27. A thin film magnetic transducer comprising

a yoke including at least one arm having at least one easy axis of magnetization, and

a coil having at least one turn, said yoke and said coil being intertwined to provide more than two flux interactions between said yoke and said at least one turn,

said arm having a plurality of elongated segments oriented obliquely to each other and having easy axes of magnetization respectively transverse to the directions of flux conduction through said segments, the easy axis of each one of said segments being perpendicular to a direction along which said segment generally extends, said segments being joined together to direct flux through said coil.

28. A thin film magnetic transducer comprising

a yoke including a single arm having at least one easy axis of magnetization, and

a coil having at least one turn, said yoke and said coil being intertwined to provide more than two flux interactions between said yoke and said at least one turn,

said arm having a plurality of elongated segments oriented obliquely to each other and having easy axes of magnetization respectively transverse to the directions of flux conduction through said segments, said segments being joined together so that flux can pass therebetween without flowing parallel to the easy axes of said segments, and

said arm including a portion of relatively small surface area adapted to be disposed adjacent to a storage medium and transfer flux between said arm and said medium, and a portion that has a relatively large surface area to cause flux in said arm to be radiated from said arm to regions adjacent to said transducer.

31. A thin film magnetic transducer comprising

a yoke including at least one arm having at least one easy axis of magnetization, and

a coil having at least one turn, said yoke and said coil being intertwined to provide more than two flux interactions between said yoke and said at least one turn,

said arm having a plurality of elongated segments each of which is disposed generally along a longitudinal axis of said transducer,

said segments being oriented obliquely to each other and having easy axes of magnetization respectively transverse to the directions of flux conduction through said segments and at an oblique angle with respect to said longitudinal axis, said segments being joined together to direct flux through said coil.