Magnetoresistance effect element, magnetic head, magnetic reproducing apparatus, and magnetic memory

• US 20040021990A1
• Filed: 03/28/2003
• Published: 02/05/2004
• Est. Priority Date: 03/28/2002
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Yoshikawa, Masatoshi, Sahashi, Masashi, Koui, Katsuhiko, Iwasaki, Hitoshi, Takagishi, Masayuki, Sakakubo, Takeo
• Granted Patent: US 7,072,153 B2
• Time in Patent Office: Days
• US Class Current: 360/324.1
• 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 5/3903 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: H01F 10/3254 the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]
• CPC Class Codes: H01F 10/3259 Spin-exchange-coupled multilayers comprising at least a nanooxide layer [NOL], e.g. with a NOL spacer
• CPC Class Codes: H01F 10/3268 the exchange coupling being asymmetric, e.g. by use of additional pinning, by using antiferromagnetic or ferromagnetic coupling interface, i.e. so-called spin-valve [SV] structure, e.g. NiFe/Cu/NiFe/FeMn
• CPC Class Codes: H10B 61/10 comprising components having two electrodes, e.g. diodes or MIM elements
• CPC Class Codes: H10B 61/22 of the field-effect transistor [FET] type
• CPC Class Codes: H10N 50/10 Magnetoresistive devices

Abstract

A magnetoresistance effect element comprises a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and a pair of electrodes electrically connected to said magnetoresistance effect film to supply a sense current perpendicularly to a film plane of said magnetoresistance effect film, The intermediate layer has a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low. The sense current preferentially flows through the second regions when the current passes the first layer. Alternatively, the concentration of oxygen in the first layer may have a two-dimensional fluctuation, and a first region where the concentration of oxygen is equal to or higher than 40 atomic % and a second region where the concentration of oxygen is equal to or lower than 35 atomic % may be provided in the first layer.

Claims

1. A magnetoresistance effect element comprising:

a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer, the nonmagnetic intermediate layer having a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low and configured to have the sense current preferentially flow through the second regions when an sense current passes the first layer; and

a pair of electrodes electrically coupled to the magnetoresistance effect film and configured to supply the sense current perpendicularly to a film plane of the magnetoresistance effect film.

2. The magnetoresistance effect element according to claim 1, wherein the first region and the second regions are formed in correspondence with a two-dimensional fluctuation of concentration of oxygen in the first layer.

3. The magnetoresistance effect element according to claim 1, wherein a composition of the nonmagnetic intermediate layer changes continuously at a boundary between the first and second regions.

4. The magnetoresistance effect element according to claim 1, wherein an ohmic characteristic is obtained when the sense current passes the first layer.

5. The magnetoresistance effect element according to claim 1, wherein the first layer includes a oxide of a element selected from the group consisting of boron (B), silicon (Si), germanium (germanium), tantalum (Ta), tungsten (W), niobium (Nb), aluminum (aluminum), molybdenum (Mo), phosphorous (P), vanadium (V), arsenic (As), antimony (Sb), zirconium (Zr), titanium (Ti), zinc (Zn), lead (Pb), thorium (Th), beryllium (Be), cadmium (Cd), a scandium (Sc), lantern (La), yttrium (Y), praseodymium (Pr), chromium (Cr), tin (Sn), gallium (Ga), Indium (In), rhodium (Rh), palladium (Pd), magnesium (Mg), lithium (Li), barium (Ba), calcium (calcium), strontium (Sr), manganese (Mn), iron (Fe), cobalt (Co), nickel (nickel), rubidium (Rb), and rare earth metals, as its main component.

6. The magnetoresistance effect element according to claim 1, wherein the first layer includes an element selected from the group consisting of copper (Cu), gold (Au), silver (Ag), platinum (Pt), palladium (Pd), iridium (Ir), and osmium (Os), in a range from 1 atomic % to 50 atomic %.

7. The magnetoresistance effect element according to claim 1, wherein the first layer is substantially crystalline.

8. The magnetoresistance effect element according to claim 1, wherein the first layer includes a oxide of a element selected from the group consisting of boron (B), silicon (Si), germanium (Ge), tungsten (W), niobium (Nb), molybdenum (Mo), phosphorous (P), vanadium (V), antimony (Sb), zirconium (Zr), titanium (Ti), zinc (Zn), a lead (Pb), chromium (Cr), tin (Sn), gallium (Ga), iron (Fe), cobalt (Co), and rare earth metals, and further includes an element selected from the group consisting of copper (Cu), gold (Au), silver (Ag), platinum (Pt), palladium (Pd), iridium (Ir), and osmium (Os), in a range from 1 atomic % to 50 atomic %.

9. The magnetoresistance effect element according to claim 1, wherein the nonmagnetic intermediate layer further has a second layer made of a non-magnetic metal.

10. The magnetoresistance effect element according to claim 9, wherein a thickness of the second layer is equal to or smaller than 1 nanometer.

11. The magnetoresistance effect element according to claim 9, wherein the nonmagnetic metal is a one selected from the group consisting of copper (Cu), gold (Au), silver (Ag), platinum (Pt), palladium (Pd), iridium (Ir), and osmium (Os).

22. The magnetoresistance effect element according to claim 9, wherein the second layer is provided between the first layer and the magnetically pinned layer, or between the first layer and the magnetically free layer.

12. A magnetoresistance effect element comprising:

a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer, the nonmagnetic intermediate layer having a first layer made of an oxide, a concentration of oxygen in the first layer having a two-dimensional fluctuation, the first layer having a first region where the concentration of oxygen is equal to or higher than 40 atomic % and a second region where the concentration of oxygen is equal to or lower than 35 atomic %; and

a pair of electrodes electrically coupled to the magnetoresistance effect film and configured to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film.

13. The magnetoresistance effect element according to claim 12, wherein a composition of the nonmagnetic intermediate layer changes continuously at a boundary between the first and second regions.

14. The magnetoresistance effect element according to claim 12, wherein an ohmic characteristic is obtained when the sense current passes the first layer.

15. The magnetoresistance effect element according to claim 12, wherein the oxide includes a element selected from the group consisting of boron (B), silicon (Si), germanium (germanium), tantalum (Ta), tungsten (W), niobium (Nb), aluminum (aluminum), molybdenum (Mo), phosphorous (P), vanadium (V), arsenic (As), antimony (Sb), zirconium (Zr), titanium (Ti), zinc (Zn), lead (Pb), thorium (Th), beryllium (Be), cadmium (Cd), a scandium (Sc), lantern (La), yttrium (Y), praseodymium (Pr), chromium (Cr), tin (Sn), gallium (Ga), Indium (In), rhodium (Rh), palladium (Pd), magnesium (Mg), lithium (Li), barium (Ba), calcium (calcium), strontium (Sr), manganese (Mn), iron (Fe), cobalt (Co), nickel (nickel), rubidium (Rb), and rare earth metals, as its main component.

16. The magnetoresistance effect element according to claim 12, wherein the first layer includes an element selected from the group consisting of copper (Cu), gold (Au), silver (Ag), platinum (Pt), palladium (Pd), iridium (Ir), and osmium (Os), in a range from 1 atomic % to 50 atomic %.

17. The magnetoresistance effect element according to claim 12, wherein the first layer is substantially crystalline,

18. The magnetoresistance effect element according to claim 12, wherein the oxide includes a element selected from the group consisting of boron (B), silicon (Si), germanium (Ge), tungsten (W), niobium (Nb), molybdenum (Mo), phosphorous (P), vanadium (V), antimony (Sb), zirconium (Zr), titanium (Ti), zinc (Zn), a lead (Pb), chromium (Cr), tin (Sn), gallium (Ga), iron (Fe), cobalt (Co), and rare earth metals, and further includes an element selected from the group consisting of copper (Cu), gold (Au), silver (Ag), platinum (Pt), palladium (Pd), iridium (Ir), and osmium (Os), in a range from 1 atomic % to 50 atomic %.

19. The inagnetoresislance effect element according to claim 12, wherein the nonmagnetic intermediate layer further has a second layer made of a non-magnetic metal.

20. The magnetoresistance effect element according to claim 19, wherein a thickness of the second layer is equal to or smaller than 1 nanometer.

21. The magnetoresistance effect element according to claim 19, wherein the non-magnetic metal is a one selected from the group consisting of copper (Cu), gold (Au), silver (Ag), platinum (Pt), palladium (Pd), iridium (Ir), and osmium (Os).

23. The magnetoresistance effect element according to claim 19, wherein the second layer is provided between the first layer and the magnetically pinned layer, or between the first layer and the magnetically free layer.

24. A magnetic head comprising a magnetoresistance effect element having;

a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and

a pair of electrodes electrically coupled to the magnetoresistance effect film to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film,

the nonmagnetic intermediate layer having a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low, and

the sense current preferentially flowing through the second regions when the current passes the first layer.

25. A magnetic head comprising a magnetoresistance effect element having;

a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and

a pair of electrodes electrically coupled to the magnetoresistance effect film to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film,

the nonmagnetic intermediate layer having a first layer made of an oxide,

a concentration of oxygen in the first layer having a two-dimensional fluctuation, and

a first region where the concentration of oxygen is equal to or higher than 40 atomic % and a second region where the concentration of oxygen is equal to or lower than 35 atomic % being provided in the first layer.

26. A magnetic reproducing apparatus which reads information magnetically recorded in a magnetic recording medium,

the magnetic reproducing apparatus comprising a magnetic head having a magnetoresistance effect element including;

a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and

a pair of electrodes electrically coupled to the magnetoresistance effect film to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film,

the nonmagnetic intermediate layer having a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low, and

the sense current preferentially flowing through the second regions when the current passes the first layer.

27. A magnetic reproducing apparatus which reads information magnetically recorded in a magnetic recording medium,

the magnetic reproducing apparatus comprising a magnetic head having a magnetoresistance effect element including:

a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and

a pair of electrodes electrically coupled to the magnetoresistance effect film to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film,

the nonmagnetic intermediate layer having a first layer made of an oxide,

a concentration of oxygen in the first layer having a two-dimensional fluctuation, and

a first region where the concentration of oxygen is equal to or higher than 40 atomic % and a second region where the concentration of oxygen is equal to or lower than 35 atomic % being provided in the first layer.

28. A magnetic memory comprising a plurality of magnetoresistance effect elements arranged in a matrix fashion,

the magnetoresistance effect element including:

a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and

a pair of electrodes electrically coupled to the magnetoresistance effect film to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film,

the nonmagnetic intermediate layer having a first layer including a first region whose resistance is relatively high and second regions whose resistance is relatively low, and

the sense current preferentially flowing through the second regions when the current passes the first layer.

29. A magnetic memory comprising a plurality of magnetoresistance effect elements arranged in a matrix fashion,

the magnetoresistance effect element including:

a magnetoresistance effect film including a magnetically pinned layer whose direction of magnetization is pinned substantially in one direction, a magnetically free layer whose direction of magnetization changes in response to an external magnetic field, and a nonmagnetic intermediate layer located between the pinned layer and the free layer; and

a pair of electrodes electrically coupled to the magnetoresistance effect film to supply a sense current perpendicularly to a film plane of the magnetoresistance effect film,

the nonmagnetic intermediate layer having a first layer made of an oxide,

a concentration of oxygen in the first layer having a two-dimensional fluctuation, and

a first region where the concentration of oxygen is equal to or higher than 40 atomic % and a second region where the concentration of oxygen is equal to or lower than 35 atomic % being provided in the first layer.