TUNNEL TYPE MAGNETIC DETECTION ELEMENT IN WHICH FE COMPOSITION OF TOP/BOTTOM SURFACE OF INSULATING BARRIER LAYER IS ADJUSTED AND MANUFACTURING METHOD THEREOF

Abstract

Described herein is a tunnel type magnetic detection element and a manufacturing method thereof. In the tunnel type magnetic detection element, an enhance layer included in a free magnetic layer (upper magnetic layer) disposed on an insulating barrier layer contacts the insulating barrier layer, which may be made of an oxide such as titanium oxide. Under the insulating barrier layer, a second pinned magnetic layer constituting a pinned magnetic layer is formed in contact with the insulating barrier layer. The Fe composition ratio of the enhance layer is greater than that of the second pinned magnetic layer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a read head including a tunnel type magnetic resistance effect element according to one embodiment, where the sectional view is taken along a plane parallel to a surface facing a recording medium.

FIG. 2 is a sectional view of a read head including a tunnel type magnetic resistance effect element according to another embodiment, where the sectional view is taken along a plane parallel to a surface facing a recording medium.

FIG. 3 is an enlarged schematic diagram of a part of the tunnel type magnetic detection element in FIG. 1.

FIG. 4 is a schematic diagram showing a crystal structure of titanium oxide.

FIG. 5 is a graph showing the range of Fe composition ratio of the lower and upper magnetic layers.

FIG. 6 is a graph showing the relationship between the Fe composition ratio Y of a enhance layer which is formed on an insulating barrier layer and the RA value.

FIG. 7 is a graph showing the relationship between the Fe composition ratio Y of the enhance layer which is formed on the insulating barrier layer and the resistance change ratio (ΔR/R).

FIG. 8 is a graph showing the Fe composition ratio Y of the enhance layer which is formed on the insulating barrier layer and a bias magnetic field Hpin of a pinned magnetic layer and also the relationship between the Fe composition ratio Y and an Ms·t value of a second pinned magnetic layer which constitutes part of the pinned magnetic layer.

FIG. 9 is a graph showing the relationship between the Fe composition ratio X of the second pinned magnetic layer which is formed on the insulating barrier layer and a RA value.

FIG. 10 is a graph showing the relationship between the Fe composition ratio X of the second pinned magnetic layer which is formed on the insulating barrier layer and a resistance change ratio (ΔR/R) FIG. 11 is a graph showing the relationship between the RA value and the resistance change ratio (ΔR/R) of each one of tunnel type magnetic detection elements according to embodiments 1 and 2 in which the Fe composition ratio of the enhance layer formed on the insulating barrier layer is greater than that of the second pinned magnetic layer formed under the insulating barrier layer and according to a comparison example 1 in which the Fe composition ratios of the enhance layer and the second pinned magnetic layer are the same.

FIG. 12 is a graph showing the relationship between the RA value and the resistance change ratio (ΔR/R) of each one of tunnel type magnetic detection elements according to a comparison example 1 in which the Fe composition ratios of the enhance layer formed on the insulating barrier layer and the second pinned magnetic layer formed under the insulating barrier layer are the same and according to comparison examples 2-1 and 2-2 in which the Fe composition ratios of the enhance layers are smaller than those of the second pinned magnetic layers.

FIG. 13 is a graph showing the relationship between the RA value and the resistance change ratio (ΔR/R) of each one of multiple tunnel type magnetic detection elements in which the Fe composition ratios of the second pinned magnetic layers are different, especially by the group base on the crystal structures.

FIG. 14 is a graph showing the resistance change ratio (ΔR/R) of each one of tunnel type magnetic detection elements according to embodiments 3 and 4 of the present invention in which the Fe composition ratio of the enhance layer formed on the insulating barrier layer is greater than that of the second pinned magnetic layer formed under the insulating barrier layer (where the Ni composition ratios of the soft magnetic layers are different between the embodiments 3 and 4 and according to a comparison example 3 in which the Fe composition ratios of the enhance layer and the second pinned magnetic layer are the same.

FIG. 15 is a graph showing magnitudes of magnetostriction of the embodiments 3 and 4 and the comparison example 3.

Claims

1. A tunnel type magnetic detection element comprising: a lower magnetic layer, an insulating barrier layer, and an upper magnetic layer sequentially stacked from below, wherein one of the magnetic layers forms at least a portion of a pinned magnetic layer having a fixed magnetization and the other magnetic layer forms at least a portion of a free magnetic layer having a magnetization that varies in accordance with an external magnetic field,wherein the insulating barrier layer is formed of an oxide, andwherein X, a composition ratio of Fe in the upper magnetic layer, is higher than Y, a composition ratio of Fe in the lower magnetic layer.

2. The tunnel type magnetic detection element according to claim 1, wherein the insulating barrier layer is formed of titanium oxide.

3. The tunnel type magnetic detection element according to claim 1, wherein the lower magnetic layer is formed of Co100-XFeX, X having units of at. %, and the upper magnetic layer is formed of Co100-YFeY, Y having units of at. %.

4. The tunnel type magnetic detection element according to claim 3, wherein X is in the range of from 0 at. % to about 50 at. %.

5. The tunnel type magnetic detection element 5 according to claim 4, wherein X is in the range of from 0 at. % to about 30 at. %.

6. The tunnel type magnetic detection element according to claim 3, wherein Y is in the range of from about 30 at. % to 100 at. %.

7. The tunnel type magnetic detection element according to claim 6, wherein Y is in the range of from about 50 at. % to 100 at. %.

8. The tunnel type magnetic detection element according to claim 1, wherein the pinned magnetic layer is formed under the insulating barrier layer, the pinned magnetic layer has a stacked layer ferri-structure in which a first pinned magnetic layer, a non-magnetic intermediate layer, and a second pinned magnetic layer are sequentially stacked from below and the second pinned magnetic layer contacts a bottom surface of the insulating harrier layer,wherein the free magnetic layer is disposed on the insulating barrier layer and the free magnetic layer comprises a stacked layer structure including an enhance layer disposed on a top surface of the insulating barrier layer and a soft magnetic layer disposed on the enhance layer, andwherein at least a part of the second pinned magnetic layer is disposed in the lower magnetic layer and at least a part of the enhance layer is disposed in the upper magnetic layer.

9. The tunnel type magnetic detection element according to claim 8, wherein the soft magnetic layer comprises a magnetostriction control region having a magnetostriction with a sign opposite to a magnetostriction of the upper magnetic layer.

10. The tunnel type magnetic detection element according to claim 9, wherein the upper magnetic layer is formed of a CoFe alloy, the magnetostriction control region is formed of NiZFe100-Z, and Z, a composition ratio of Ni, is greater than about 81.5 at. % and equal to or lower than 100 at. %.

11. The tunnel type magnetic detection element according to claim 1, wherein the free magnetic layer is formed under the insulating barrier layer and has a structure in which a soft magnetic layer and an enhance layer are sequentially stacked from below and the enhance layer contacts a bottom surface of the insulating barrier layer, andwherein the pinned magnetic layer is formed on the insulating barrier layer, the pinned magnetic layer includes a stacked layer ferri-structure in which a second pinned magnetic layer contacting the top surface of the insulating barrier layer, a non-magnetic intermediate layer, and a first pinned magnetic layer are stacked sequentially from below, at least a part of the enhance layer is disposed in the lower magnetic layer, and at least a part of the second pinned magnetic layer is disposed in the upper magnetic layer.

12. A method of manufacturing a tunnel type magnetic detection element, the method comprising the steps of: (a) forming a lower magnetic layer;(b) forming a metal layer or a semiconductor layer on the lower magnetic layer;(c) forming an insulating barrier layer by oxidizing the metal layer or the semiconductor layer; and(d) forming an upper magnetic layer on the insulating barrier layer out of a magnetic material wherein X, a composition ratio of Fe in the magnetic material of the upper magnetic layer, is higher than Y, a composition ratio of Fe in a magnetic material of the lower magnetic layer.

13. The method according to claim 12, wherein the metal layer is a titanium layer and the insulating barrier layer is formed of titanium oxide.

14. The method according to claim 12, wherein the lower magnetic layer comprises Co100-XFeX, X being in the range of from 0 at. % to about 50 at. %.

15. The method according to claim 14, wherein X is in the range of from 0 at. % to about 30 at. %.

16. The method according to claim 12, wherein the upper magnetic layer comprises Co100-YFeY, Y being in the range of from about 30 at. % to 100 at. %.

17. The method according to claim 16, wherein Y is in the range of from about 50 at. % to 100 at. %.