Magneto-resistance effect type head and information reproducing apparatus

• US 6,493,197 B2
• Filed: 09/18/2001
• Issued: 12/10/2002
• Est. Priority Date: 06/29/1999
• Status: Expired due to Fees

• Current Assignee: Fujitsu Limited
• Original Assignee: Fujitsu Limited
• Inventors: Ito, Junichi, Kanai, Hitoshi, Kanamine, Michiaki
• Primary Examiner(s): Letscher, George J.
• Application Number:
  US09/955,358
• Publication Number:
  US 20020008949A1
• Time in Patent Office: 448 Days
• Field of Search: 360/324.12, 360/322, 360/324.1, 360/327.24, 360/327.33
• US Class Current: 360/324.12
• 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: G11B 2005/3996 large or giant magnetoresistive effects [GMR], e.g. as generated in spin-valve [SV] devices
• CPC Class Codes: G11B 5/00 Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor G11B11/00 and G11B13/00 take precedence
• 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 5/3903 using magnetic thin film layers or their effects, the films being part of integrated structures
• CPC Class Codes: G11B 5/3932 Magnetic biasing films

Abstract

The present invention provides a magneto-resistance effect type head for reproducing, with a high sensitivity, information recorded at a high recording density on a recording medium while inhibiting occurrence of the Barkhausen noise, including a magneto-resistance effect element comprised of a multi-layer film containing a free magnetic layer having its magnetization direction changing in correspondence with an external magnetic field, an insulating film, a non-magnetic underlying layer formed on the insulating film, and one pair of magnetic domain-wall control layers formed on the underlying layer in its in-face direction with a predetermined spacing therebetween, for inhibiting movement of magnetic domain wall of the free magnetic layer, in such a configuration that the free magnetic layer has its both ends directly stacked on the pair of the magnetic domain-wall control layers and also has its middle part directly stacked on the underlying layer.

Claims

1. A magneto-resistance effect type head equipped with a magneto-resistance effect element exhibiting a resistance change in correspondence with an intensity of an external magnetic field, for detecting a value of a resistance of said magneto-resistance effect element to thereby detect said intensity of magnetic field, said magneto-resistance effect element comprised of a multi-layer film containing a free magnetic layer having magnetization direction changing in correspondence with an external magnetic field, said head comprising:

an insulating layer made of an insulating material;

a non-magnetic underlying layer formed on said insulating layer; and

one pair of magnetic domain-wall control layers formed on said underlying layer in an in-face direction thereof with a predetermined spacing therebetween, for controlling movement of a magnetic domain wall of said free magnetic layer,

wherein said free magnetic layer is formed in such a manner as to have both ends thereof stacked directly on said pair of magnetic domain-wall control layers respectively and to have a middle portion thereof stacked directly on said underlying layer.

2. The magneto-resistance effect type head according to claim 1, wherein said underlying layer is made of Ta.

3. A magneto-resistance effect type head equipped with a magneto-resistance effect element exhibiting a resistance change in correspondence with an intensity of an external magnetic field, for detecting a value of a resistance of said magneto-resistance effect element to thereby detect said intensity of magnetic field, said magneto-resistance effect element comprised of a multi-layer film containing a free magnetic layer having magnetization direction changing in correspondence with an external magnetic field, said head comprising:

an insulating layer made of an insulating material;

a non-magnetic underlying layer formed on said insulating layer;

one pair of electrodes formed on said underlying layer in an in-face direction thereof with a predetermined spacing therebetween; and

one pair of magnetic domain-wall control layers stacked, in formation, respectively on said pair of electrodes on said underlying layer in an in-face direction thereof with a predetermined spacing therebetween, for controlling movement of a magnetic domain wall of said free magnetic layer,

wherein said free magnetic layer is formed in such a manner as to have both ends thereof stacked directly on said pair of magnetic domain-wall control layers respectively and to have a middle portion thereof stacked directly on said underlying layer.

4. The magneto-resistance effect type head according to claim 3, wherein said underlying layer is made of Ta.

5. The magneto-resistance effect type head according to claim 3, wherein said electrode has as a top layer thereof at least one layer including a layer made of Ta.

6. The magneto-resistance effect type head according to claim 3, wherein said magnetic domain-wall control layer includes a hard magnetic layer made of a CoPt-based alloy.

7. An information reproducing apparatus equipped with a magnetic head which is arranged in contact or in near contact with a magnetic recording medium on which information is recorded by magnetization to thereby detect magnetization at each point on said magnetic recording medium, for reproducing information in correspondence with magnetization detected by said magnetic head at each point on said magnetic recording medium, wherein:

said magnetic head is equipped with a magneto-resistance effect element which is comprised of a multi-layer film containing a free magnetic layer having a magnetization direction changing in correspondence with an external magnetic field and also which exhibits a resistance change in correspondence with an intensity of an external magnetic field, for detecting a value of a resistance of said magneto-resistance effect element to thereby detect said intensity of magnetic field, said magnetic head comprising;

an insulating layer made of an insulating material;

a non-magnetic underlying layer formed on said insulating layer; and

one pair of magnetic domain-wall control layers formed on said underlying layer in an in-face direction thereof with a predetermined spacing therebetween, for controlling movement of a magnetic domain wall of said free magnetic layer; and

said free magnetic layer is formed in such a manner as to have both ends thereof stacked directly on said pair of magnetic domain-wall control layers respectively and to have a middle portion thereof stacked directly on said underlying layer.

8. An information reproducing apparatus equipped with a magnetic head which is arranged in contact or in near contact with a magnetic recording medium on which information is recorded by magnetization to thereby detect magnetization at each point on said magnetic recording medium, for reproducing information in correspondence with magnetization detected by said magnetic head at each point on said magnetic recording medium, wherein:

said magnetic head is equipped with a magneto-resistance effect element which is comprised of a multi-layer film containing a free magnetic layer having a magnetization direction changing in correspondence with an external magnetic field and also which exhibits a resistance change in correspondence with an intensity of an external magnetic field, for detecting a value of a resistance of said magneto-resistance effect element to thereby detect said intensity of magnetic field, said magnetic head comprising;

an insulating layer made of an insulating material;

a non-magnetic underlying layer formed on said insulating layer;

one pair of electrodes formed on said underlying layer in an in-face direction thereof with a predetermined spacing therebetween, for flowing a current to said magneto-resistance effect element; and

one pair of magnetic domain-wall control layers stacked, in formation, respectively on said pair of electrodes on said underlying layer in an in-face direction thereof with a predetermined spacing therebetween, for controlling movement of a magnetic domain wall of said free magnetic layer; and

said free magnetic layer is formed in such a manner as to have both ends thereof stacked directly on said pair of magnetic domain-wall control layers respectively and to have a middle portion thereof stacked directly on said underlying layer.