MAGNETIC TRANSDUCER HAVING A PLURALITY OF MAGNETIC LAYERS STACKED ALTERNATELY WITH A PLURALITY OF NONMAGNETIC LAYERS AND A FIXED-ORIENTATION-OF-MAGNETIZATION LAYER AND THIN FILM MAGNETIC HEAD INCLUDING THE MAGNETIC TRANSDUCER

• US 6,603,642 B1
• Filed: 10/11/2000
• Issued: 08/05/2003
• Est. Priority Date: 03/15/2000
• Status: Expired due to Fees

• Current Assignee: TDK Corporation
• Original Assignee: TDK Corporation
• Inventors: Shimazawa, Koji, Araki, Satoru
• Primary Examiner(s): EVANS, JEFFERSON A
• Application Number:
  US09/685,891
• Time in Patent Office: 1,028 Days
• Field of Search: 360/317, 360/319, 360/324-324
• US Class Current: 360/324
• CPC Class Codes: B82Y 10/00 Nanotechnology for information processing, storage or transmission, e.g. quantum computing or single electron logic
• 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 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: G11B 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: G11B 5/3916 Arrangements in which the active read-out elements are coupled to the magnetic flux of the track by at least one magnetic thin film flux guide
• CPC Class Codes: G11B 5/398 Specially shaped layers

Abstract

An object of the invention is to provide a magnetic transducer and a thin film magnetic head using the same, which can be manufactured by a simple manufacturing process and can obtain good output. The thin film magnetic head has a stack including a plurality of magnetic layers stacked alternately with a plurality of nonmagnetic layers. A layer having the fixed orientation of magnetization is formed on at least one side of the stack in the direction of stacking. The layer has a stacked structure comprising an antiferromagnetic layer and an exchange coupling layer exchange coupling with the antiferromagnetic layer. The magnetic layers of the stack are changed into a single magnetic domain by a magnetic field generated by exchange coupling between the antiferromagnetic layer and the exchange coupling layer so as to prevent Barkhausen noise. Since the layer is formed on at least one side of the stack in the direction of stacking, a manufacturing process is simplified.

Claims

1. A magnetic transducer comprising:

a stack having a plurality of magnetic layers stacked alternately with a plurality of nonmagnetic layers; and

a fixed-orientation-of-magnetization layer formed on at least one side of the stack in the direction of stacking and having magnetization fixed in a fixed direction, wherein the stack has a projecting portion facing a signal magnetic field.

2. A magnetic transducer according to claim 1, wherein a length of the projecting portion along the projecting direction thereof is 0.1 μ

m or less.

3. A magnetic transducer according to claim 1, further comprising a magnetic field capture limiting portion located in an area on a side of the stack facing a signal magnetic field, for partially limiting an effect of a signal magnetic field on the stack.

4. A magnetic transducer according to claim 1, further comprising a magnetic field capture limiting portion made of a magnetic material and located in an area corresponding to a part of the stack on a side of the stack facing an signal magnetic field.

5. A thin film magnetic head having a magnetic transducer according to claim 1.

6. A magnetic transducer comprising:

a stack having a plurality of magnetic layers stacked alternately with a plurality of nonmagnetic layers; and

a fixed-orientation-of-magnetization layer formed on at least one side of the stack in the direction of stacking and having magnetization fixed in a fixed direction, wherein the antiferromagnetic coupling energy induced between two magnetic layers adjacent to each of the plurality of nonmagnetic layers is from 0.1×

10<sup>−

4</sup> J/m² to 2.0×

10<sup>−

4</sup> J/m² inclusive.

7. A magnetic transducer according to claim 6, further comprising:

a magnetic domain control layer formed on at least one side of the stack in the direction of stacking, for controlling the orientations of magnetizations of the magnetic layers.

8. A magnetic transducer according to claim 6, further comprising:

a magnetic field applying layer formed on at least one side of the stack in the direction of stacking, for applying a magnetic field in a fixed direction to at least a part of the stack.

9. A thin film magnetic head having a magnetic transducer according to claim 6.

10. A thin film magnetic head according to claim 9 further comprising a current path for passing a current through the stack in the direction of stack.

11. A thin film magnetic head according to claim 10 further comprising a pair of shield layers for sandwiching the stack therebetween with a pair of gap layers in between, wherein the gap layers and the shield layers function as the current path.

12. A magnetic transducer comprising:

a stack having a plurality of magnetic layers stacked alternately with a plurality of nonmagnetic layers; and

a fixed-orientation-of-magnetization layer formed on at least one side of the stack in the direction of stacking and having magnetization fixed in a fixed direction, wherein the stack is divided into a plurality of regions in the direction of stacking, and at least two regions of the plurality of regions differ from each other in a material or composition of the magnetic layers and in their cross-sectional profiles.

13. A magnetic transducer according to claim 12, wherein the stack has a first region where the magnetic layers are made of a material containing at least nickel in a group including nickel, cobalt, iron, chromium, tantalum, rhodium, molybdenum, zirconium and niobium, and a second region where the magnetic layers are made of a material containing at least cobalt in a group including nickel, cobalt and iron.

14. A thin film magnetic head having a magnetic transducer according to claim 12.