TUNNEL-TYPE MAGNETIC DETECTING DEVICE HAVING LAMINATED SEED LAYER

Abstract

A tunnel-type magnetic detecting device is provided. The tunnel-type magnetic detecting device is capable of stably reducing the surface roughness of an insulating barrier layer, and capable of properly improving an MR effect typified by a resistance changing rate. A seed layer is formed in a laminated structure of an NiFeCr layer and an Al layer. This makes it possible to stably reduce the surface roughness of the insulating barrier layer as compared with a related art in which a seed layer is formed in a single-layer structure of an NiFeCr layer. Accordingly, according to the tunnel-type magnetic detecting device of the invention, the MR property typified by an excellent resistance changing rate (ΔR/R) can be obtained stably.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of one embodiment of the structure of a thin film magnetic head including a tunnel-type magnetic detecting device;

FIG. 2 is a sectional view of the structure of one embodiment of a thin film magnetic head including a tunnel-type magnetic detecting device;

FIG. 3 is a partially enlarged schematic view showing one embodiment of a seed layer and an antiferromagnetic layer thereon in the tunnel-type magnetic detecting device shown in FIG. 1 in an enlarged manner, and a distribution chart showing the Al concentration of the seed layer and antiferromagnetic layer;

FIG. 4 is a partially enlarged schematic view showing one embodiment of a seed layer and an antiferromagnetic layer thereon in the tunnel-type magnetic detecting device shown in FIG. 2 in an enlarged manner, and a distribution chart showing the Al concentration and Co concentration of the seed layer and antiferromagnetic layer; and

FIG. 5 is a graph showing the relationship between the total thickness of a seed layer in each of spin-valve-type thin film devices in Examples 3 and 8 and Comparative Example, and an interlayer-coupling magnetic field (Hin) which acts between a free magnetic layer and a fixed magnetic layer.

Claims

1. A tunnel-type magnetic detecting device comprising: a magnetoresistive effect part having a fixed magnetic layer, and a free magnetic layer which faces the fixed magnetic layer with an insulating barrier layer therebetween and which varies in magnetization by an external magnetic field; anda seed layer provided below the magnetoresistive effect part,wherein the seed layer includes an Al layer laminated on an NiFeCr layer.

2. A tunnel-type magnetic detecting device comprising: a magnetoresistive effect part having a fixed magnetic layer, and a free magnetic layer which faces the fixed magnetic layer with an insulating barrier layer therebetween and which varies in magnetization by an external magnetic field; anda seed layer provided below the magnetoresistive effect part,wherein the seed layer includes a Co layer laminated on an NiFeCr layer, and an Al layer laminated on the Co layer.

3. A tunnel-type magnetic detecting device comprising: a magnetoresistive effect part having a fixed magnetic layer, and a free magnetic layer which faces the fixed magnetic layer with an insulating barrier layer therebetween and which varies in magnetization by an external magnetic field; anda seed layer provided below the magnetoresistive effect part,wherein the seed layer includes mainly NiFeCr, and the average concentration of Al in a surface region of the seed layer is higher than the average concentration of Al in a seed region below the surface region.

4. A tunnel-type magnetic detecting device comprising: a magnetoresistive effect part having a fixed magnetic layer, and a free magnetic layer which faces the fixed magnetic layer with an insulating barrier layer therebetween and which varies in magnetization by an external magnetic field; anda seed layer provided below the magnetoresistive effect part,wherein the seed layer includes mainly NiFeCr, a high-concentration Co region and a high-concentration Al region provided above the high-concentration Co region exist in a surface region of the seed layer.

5. The tunnel-type magnetic detecting device according to claim 4, wherein the average concentration of Co in the high-concentration Co region is higher than the average concentration of Co in a seed layer below the high-concentration Co region, and the average concentration of Al in the high-concentration Al region is higher than the average concentration of Al in a seed region below the high-concentration Al region.