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AssigneeNone recorded
InventorsHiromasa Takahashi, Reiko Arai, Susumu Soeya
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There are provided a magnetoresistive sensor of the type of flowing a signal sensing current perpendicular to the plane to improve resolution at reproducing a signal, a magnetic head using the magnetoresistive sensor, and a magnetic disk apparatus. A magnetoresistive sensor comprising a substrate, a pair of magnetic shield layers consisting of a lower magnetic shield layer and an upper magnetic shield layer, a magnetoresistive sensor layer, disposed between the pair of magnetic shield layers, an electrode terminal for flowing a signal current perpendicular to the plane of the magnetoresistive sensor layer, and magnetic domain control layers for controlling Barkhausen noise of the magnetoresistive sensor layer, wherein the magnetic domain control layers disposed in contact with opposite ends of the magnetoresistive sensor layer consist of a material having high electric resistivity and with a specific resistance not less than 10 mΩcm so as to give the magnetoresistive sensor having excellent reproducing resolution. The sensor is used to provide a magnetic head having excellent reproducing resolution and a magnetic disk apparatus.
A magnetoresistive sensor including a substrate, a pair of magnetic shield layers consisting of a lower magnetic shield layer and an upper magnetic shield layer, a magnetoresistive sensor layer disposed between the pair of magnetic shields, an electrode terminal for flowing a signal current perpendicular to the plane of the magnetoresistive sensor layer, and magnetic domain control layers for controlling Barkhausen noise of said magnetoresistive sensor layer, wherein said magnetic domain control layers disposed on opposite ends of the magnetoresistive sensor layer in a region from the end surface of a media-opposed surface side of the magnetoresistive sensor layer to the depth position are made of a material having a specific resistance not less than 10 mΩcm, and are in contact with at least opposite end surfaces of said magnetoresistive sensor layer in said region.
A magnetoresistive sensor including a substrate, a pair of magnetic shield layers consisting of a lower magnetic shield layer and an upper magnetic shield layer, a magnetoresistive sensor layer disposed between the pair of magnetic shields, an electrode terminal for flowing a signal current perpendicular to the plane of the magnetoresistive sensor layer, and magnetic domain control layers for controlling Barkhausen noise of said magnetoresistive sensor layer, wherein a material consisting of said magnetic domain control layers disposed on opposite ends of the magnetoresistive sensor layer in the region from the end surface of the media-opposed surface side of the magnetoresistive sensor layer to the depth position is a compound having a composition of R203 containing at least R (R═Fe, Co, Mn, and Ni) and oxygen (O) and has a spinel lattice and a (400) orientation plane, and the magnetic domain control layers are in contact with at least opposite end surfaces of said magnetoresistive sensor layer in said region.
Dependencies are inferred from the claim text.
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Using galvano-magnetic devices: magnetoresistive devices
Nanotechnology for information processing, storage or transmission
Nanomagnetism
Using magneto-resistive devices or effects: using magnetic thin film layers or their effects, the films being part of integrated structures
Term end not estimated
1. Field of the Invention
The present invention relates to a magnetoresistive sensor including magnetic domain control layers for the magnetoresistive sensor for reading back magnetically recorded information, a magnetic head, and a magnetic disk apparatus. More specifically, it relates to a magnetoresistive sensor having excellent reproducing resolution, a magnetic head using the same, and a magnetic disk apparatus.
2. Description of the Related Art
FIG. 1 is a diagram showing the sectional structure of the media-opposed surface side of the magnetoresistive sensor of Example 1 of the present invention and the position of a magnetic domain control layer;
FIG. 2 is a cross-sectional view of the depth direction of the magnetoresistive sensor of Example 1 of the present invention;
FIG. 3 is a cross-sectional view of the media-opposed surface side of Example 1 (3) of the present invention showing the position relation between the magnetic domain control layer having high electric resistivity and the magnetoresistive sensor layer;
Embodiments of the present invention will be described based on the examples with reference to the drawings.
FIGS. 1 and 2 are diagrams showing the structure of a magnetoresistive sensor as one embodiment according to the present invention viewed from the media-opposed surface and section of the plane perpendicular to the depth direction, respectively. Arrow 110 in the drawing denotes the depth direction.
On a substrate 101 is formed a base insulating layer 102, made of, for example, alumina. After subjected to precision polishing by means of chemimechanical polishing (CMP), a lower magnetic shield layer 103 is formed thereon. This is made of Ni81Fe19 having a thickness of 2 μm manufactured by, for example, the sputtering method, the ion beam sputtering method, or the plating method. A resist mask is patterned in a predetermined size in this layer, and other portions thereof are subjected to ion milling to strip off the resist. Al2O3 is grown thereon to fill in portions 104 removed by ion milling. After this is subjected to CMP, an electrode layer made of Cu or Ru (not shown) is grown by 20 nm, so as to form a drawing electrode layer 111 in a portion away from the sensor portion. This is, for example, a layer made of Ta, Au and Ta.