Magneto-resistive effect device, magnetic head gimbal assembly, magnetic recording/reproduction device, strain sensor, pressure sensor, blood pressure sensor, and structural health monitoring sensor

• US 9,435,868 B2
• Filed: 03/17/2015
• Issued: 09/06/2016
• Est. Priority Date: 03/24/2011
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Giddings, Devin, Fukuzawa, Hideaki, Fuji, Yoshihiko, Hara, Michiko, Yuasa, Hiromi
• Primary Examiner(s): Renner, Craig A.
• Application Number:
  US14/659,762
• Publication Number:
  US 20150185296A1
• Time in Patent Office: 539 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: A61B 2562/0247 Pressure sensors
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/022 by applying pressure to close blood vessels, e.g. against the skin; Ophthalmodynamometers
• CPC Class Codes: G01R 33/091 Constructional adaptation of the sensor to specific applications
• CPC Class Codes: G01R 33/093 using multilayer structures, e.g. giant magnetoresistance sensors thin magnetic films H01F10/00
• 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 5/3906 Details related to the use of magnetic thin film layers or to their effects
• CPC Class Codes: G11B 5/399 with intrinsic biasing, e.g. provided by equipotential strips
• CPC Class Codes: H01F 10/30 characterised by the composition of the intermediate layers , e.g. seed, buffer, template, diffusion preventing, cap layers H01F10/06 and H01F10/32 take precedence
• CPC Class Codes: H01F 10/325 the spacer being noble metal
• 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: H10N 50/10 Magnetoresistive devices

Abstract

According to one embodiment, a magneto-resistive effect device, includes a stacked body stacked on a substrate, a pair of first electrodes that feeds current to the stacked body, a strain introduction member, and a second electrode for applying a voltage to the strain introduction member. The stacked body includes a first magnetic layer that includes one or more metals selected from the group consisting of iron, cobalt, and nickel, a second magnetic layer stacked on the first magnetic layer, having a composition that is different from the first magnetic layer, and a spacer layer disposed between the first magnetic layer and the second magnetic layer.

Claims

1. A strain sensor comprising:

a substrate being deformable;

a first electrode;

a second electrode provided between the first electrode and the substrate; and

a stacked body including

a first magnetic layer provided between the first electrode and the second electrode, the first magnetic layer having a first magnetization,

a second magnetic layer provided between the first magnetic layer and the second electrode, the second magnetic layer having a second magnetization, and

a first spacer layer provided between the first magnetic layer and the second magnetic layer,

wherein

the first and second electrodes supply to the stacked body current that flows along a stacking direction of the stacked body, the first magnetization changes in accordance with a first external strain applied to the stacked body, the first external strain has a first component along a first direction, the external strain is generated by a deformation of the substrate to cause a resistance between the first and second electrodes to be changed,

the second magnetization changes in accordance with a second external strain applied to the stacked body, the second external strain has a second component along a second direction different from the first direction, the second external strain is generated by the deformation, and

the first and second external strains are detected by the change in the resistance.

2. The strain sensor according to claim 1, wherein the first magnetic layer has a positive magnetostriction coefficient, and the second magnetic layer has a negative magnetostriction coefficient.

3. The strain sensor according to claim 1, wherein in a state where the first external strain is not applied, the first magnetization is parallel or antiparallel with the second magnetization.

4. The strain sensor according to claim 1, wherein the first magnetic layer has an oxide layer including one or more metals selected from the group consisting of iron, cobalt, and nickel.

5. The strain sensor according to claim 1, wherein the second magnetic layer includes one or more metals selected from the group consisting of nickel and samarium iron (SmFe).

6. The strain sensor according to claim 1, wherein the first spacer layer includes at least one of an oxide of one metal selected from the group consisting of aluminum, titanium, zinc, silicon, hafnium, tantalum, molybdenum, tungsten, niobium, chromium, magnesium, and zirconium, and a nitride of one metal selected from the group consisting of aluminum, titanium, zinc, silicon, hafnium, tantalum, molybdenum, tungsten, niobium, chromium, magnesium, and zirconium.

7. The strain sensor according to claim 1, further comprising a third magnetic layer;

and

a second spacer layer,

the second magnetic layer being disposed between the first spacer layer and the third magnetic layer,

the third magnetic layer having a third magnetization being fixed, and

the second spacer layer being provided between the second magnetic layer and the third magnetic layer.

8. The strain sensor according to claim 1, wherein the substrate includes

a membrane being deformable, and

a support part supporting the membrane,

the stacked body is provided between the membrane and the first electrode, and

the second electrode is provided between the membrane and the stacked body.

9. The strain sensor according to claim 1, further comprising

a plurality of word lines extending in a fourth direction crossing a third direction from the first magnetic layer toward the second magnetic layer;

and

a plurality of bit lines extending in a fifth direction crossing the fourth direction and the third direction,

the stacked body being provided in a plurality,

each of the stacked bodies being connected with one of the plurality of word lines and one of the plurality of bit lines.

10. The strain sensor according to claim 1, wherein the first magnetic layer has a first composition including one or more metals selected from the group consisting of iron, cobalt, and nickel, and

the second magnetic layer has a composition different from the first composition.

11. The strain sensor according to claim 1, wherein the second direction is opposite to the first direction.

12. A pressure sensor, comprising:

a strain sensor including;

a substrate including;

a membrane being deformable, and

a support part supporting the membrane;

a first electrode;

a second electrode provided between the first electrode and the membrane;

a stacked body including

a first magnetic layer provided between the first electrode and the second electrode, the first magnetic layer having a first magnetization,

a second magnetic layer provided between the first magnetic layer and the second electrode, the second magnetic layer having a second magnetization, and

a first spacer layer provided between the first magnetic layer and the second magnetic layer,

wherein the first and second electrodes supply to the stacked body current that flows along a stacking direction of the stacked body,

the first magnetization changes in accordance with a first external strain applied to the stacked body, the first external strain has a first component along a first direction, the external strain is generated by a deformation of the membrane to cause a resistance between the first and second electrodes to be changed,

the second magnetization changes in accordance with a second external strain applied to the stacked body, the second external strain has a second component along a second direction different from the first direction, the second external strain is generated by the deformation,

the first and second external strains are detected by the change in the resistance, and

an external pressure is detected by detecting the external strain generated by the external pressure.

13. The pressure sensor according to claim 12, wherein the first magnetic layer has a first composition including one or more metals selected from the group consisting of iron, cobalt, and nickel, and

the second magnetic layer has a composition different from the first composition.

14. The pressure sensor according to claim 12, wherein the second direction is opposite to the first direction.

15. A blood pressure sensor configured to monitor a blood pressure of a person or an animal, the blood pressure sensor comprising:

a strain sensor including;

a substrate being deformable;

a first electrode;

a second electrode provided between the first electrode and the substrate; and

a stacked body including

a first magnetic layer provided between the first electrode and the second electrode, the first magnetic layer having a first magnetization,

a second magnetic layer provided between the first magnetic layer and the second electrode, the second magnetic layer having a second magnetization, and

a first spacer layer provided between the first magnetic layer and the second magnetic layer,

wherein

the first and second electrodes supply to the stacked body current that flows along a stacking direction of the stacked body,

the first magnetization changes in accordance with a first external strain applied to the stacked body, the first external strain has a first component along a first direction, the external strain is generated by a deformation of the substrate to cause a resistance between the first and second electrodes to be changed,

the second magnetization changes in accordance with a second external strain applied to the stacked body, the second external strain has a second component along a second direction different from the first direction, the second external strain is generated by the deformation,

the first and second external strains are detected by the change in the resistance, and

a blood pressure is detected by detecting the external strain generated by the blood pressure.

16. The blood pressure sensor according to claim 15, wherein the first magnetic layer has a first composition including one or more metals selected from the group consisting of iron, cobalt, and nickel, and

the second magnetic layer has a composition different from the first composition.

17. The blood pressure sensor according to claim 15, the second direction is opposite to the first direction.

18. A structural health monitoring sensor configured to perform structural condition monitoring to monitor a strain state of a bridge or building structure, the structural health monitoring sensor comprising:

a strain sensor including;

a substrate being deformable;

a first electrode;

a second electrode provided between the first electrode and the substrate; and

a stacked body including

a first magnetic layer provided between the first electrode and the second electrode, the first magnetic layer having a first magnetization,

a second magnetic layer provided between the first magnetic layer and the second electrode, the second magnetic layer having a second magnetization, and

a first spacer layer provided between the first magnetic layer and the second magnetic layer,

wherein

the first and second electrodes supply to the stacked body current that flows along a stacking direction of the stacked body,

the first magnetization changes in accordance with a first external strain applied to the stacked body, the first external strain has a first component along a first direction, the external strain is generated by a deformation of the substrate to cause a resistance between the first and second electrodes to be changed,

the second magnetization changes in accordance with a second external strain applied to the stacked body, the second external strain has a second component along a second direction different from the first direction, the second external strain is generated by the deformation,

the first and second external strains are detected by the change in the resistance, and

the first and second external strains are changed in accordance with a change of a strain state.

19. The structural health monitoring sensor according to claim 18, wherein the first magnetic layer has a first composition including one or more metals selected from the group consisting of iron, cobalt, and nickel, and

the second magnetic layer has a composition different from the first composition.

20. The structural health monitoring sensor according to claim 18, wherein the second direction is opposite to the first direction.

21. A strain sensor comprising:

a substrate being deformable;

a first electrode;

a second electrode provided between the first electrode and the substrate; and

a stacked body including

a first magnetic layer provided between the first electrode and the second electrode, the first magnetic layer having a first magnetization,

a second magnetic layer provided between the first magnetic layer and the second electrode, the second magnetic layer having a second magnetization, and

a first spacer layer provided between the first magnetic layer and the second magnetic layer,

wherein

the first and second electrodes supply to the stacked body current that flows along a stacking direction of the stacked body,

the first magnetization changes in accordance with a first external strain applied to the stacked body, the external strain is generated by a deformation of the substrate to cause a resistance between the first and second electrodes to be changed,

the second magnetization changes in accordance with a second external strain applied to the stacked body, the second external strain is generated by the deformation,

the first external strain is one of a tensile strain and a compressive strain,

the second external strain is the other of the tensile strain and the compressive strain, and

the first and second external strains are detected by the change in the resistance.

22. A pressure sensor, comprising:

a strain sensor including

a substrate including

a membrane being deformable, and

a support part supporting the membrane;

a first electrode;

a second electrode provided between the first electrode and the membrane,

a stacked body including

a first magnetic layer provided between the first electrode and the second electrode, the first magnetic layer having a first magnetization,

a second magnetic layer provided between the first magnetic layer and the second electrode, the second magnetic layer having a second magnetization, and

a first spacer layer provided between the first magnetic layer and the second magnetic layer, and

wherein

the first and second electrodes supply to the stacked body current that flows along a stacking direction of the stacked body,

the first magnetization changes in accordance with a first external strain applied to the stacked body, the external strain is generated by a deformation of the membrane to cause a resistance between the first and second electrodes to be changed,

the second magnetization changes in accordance with a second external strain applied to the stacked body, the second external strain is generated by the deformation,

the first external strain is one of a tensile strain and a compressive strain,

the second external strain is the other of the tensile strain and the compressive strain,

the first and second external strains are detected by the change in the resistance, and

an external pressure is detected by detecting the external strain generated by the external pressure.

23. A blood pressure sensor configured to monitor a blood pressure of a person or an animal, the blood pressure sensor comprising:

a strain sensor including;

a substrate being deformable;

a first electrode;

a second electrode provided between the first electrode and the substrate; and

a stacked body including

a first magnetic layer provided between the first electrode and the second electrode, the first magnetic layer having a first magnetization,

a second magnetic layer provided between the first magnetic layer and the second electrode, the second magnetic layer having a second magnetization, and

a first spacer layer provided between the first magnetic layer and the second magnetic layer,

wherein

the first and second electrodes supply to the stacked body current that flows along a stacking direction of the stacked body,

the first magnetization changes in accordance with a first external strain applied to the stacked body, the external strain is generated by a deformation of the substrate to cause a resistance between the first and second electrodes to be changed,

the second magnetization changes in accordance with a second external strain applied to the stacked body, the second external strain is generated by the deformation,

the first external strain is one of a tensile strain and a compressive strain,

the second external strain is the other of the tensile strain and the compressive strain,

the first and second external strains are detected by the change in the resistance, and

a blood pressure is detected by detecting the external strain generated by the blood pressure.

24. A structural health monitoring sensor configured to perform structural condition monitoring to monitor a strain state of a bridge or building structure, the structural health monitoring sensor comprising:

a strain sensor including;

a substrate being deformable;

a first electrode;

a second electrode provided between the first electrode and the substrate; and

a stacked body including

a first magnetic layer provided between the first electrode and the second electrode, the first magnetic layer having a first magnetization,

a second magnetic layer provided between the first magnetic layer and the second electrode, the second magnetic layer having a second magnetization, and

a first spacer layer provided between the first magnetic layer and the second magnetic layer,

wherein

the first and second electrodes supply to the stacked body current that flows along a stacking direction of the stacked body,

the first magnetization changes in accordance with a first external strain applied to the stacked body, the external strain is generated by a deformation of the substrate to cause a resistance between the first and second electrodes to be changed,

the second magnetization changes in accordance with a second external strain applied to the stacked body, the second external strain is generated by the deformation,

the first external strain is one of a tensile strain and a compressive strain,

the second external strain is the other of the tensile strain and the compressive strain,

the first and second external strains are detected by the change in the resistance, and

the first and second external strains are changed in accordance with a change of a strain state.