Magnetometric sensor and current sensor

1. A magnetometric sensor comprising:

a magnetoresistance effect element having a sensitivity axis in a specific direction, wherein

the magnetoresistance effect element has a layered structure on a substrate, the layered structure comprising a fixed magnetic layer and a free magnetic layer stacked with a nonmagnetic material layer interposed therebetween;

the magnetoresistance effect element includes a first antiferromagnetic layer on the free magnetic layer on the opposite side to the side facing the nonmagnetic material layer to cause an exchange coupling bias between the first antiferromagnetic layer and the free magnetic layer to make the magnetization direction of the free magnetic layer in a prescribed direction in a state of permitting variation in magnetization; and

the free magnetic layer includes a misfit-reducing sub-layer for decreasing the lattice mismatch of the free magnetic layer with the first antiferromagnetic layer.

2. The magnetometric sensor according to claim 1 , wherein the free magnetic layer includes:

a misfit-reducing sub-layer for decreasing the lattice mismatch of the free magnetic layer with the first antiferromagnetic layer;

a first free magnetic sub-layer disposed between the misfit-reducing sub-layer and the nonmagnetic material layer; and

a second free magnetic sub-layer disposed between the misfit-reducing sub-layer and the first antiferromagnetic layer and ferromagnetically coupled to the first free magnetic sub-layer.

3. The magnetometric sensor according to claim 2 , wherein

the misfit-reducing sub-layer and the second free magnetic sub-layer each have a face-centered cubic (fcc) structure; and

the lattice spacing of the fcc(111) plane of the misfit-reducing sub-layer is larger than that of the fcc(111) plane of the second free magnetic sub-layer.

4. The magnetometric sensor according to claim 2 , wherein the misfit-reducing sub-layer contains at least one selected from the group consisting of Pt, Pd, Ta, and W.

5. The magnetometric sensor according to claim 2 , wherein

the first antiferromagnetic layer contains a platinum group element and Mn.

6. The magnetometric sensor according to claim 2 , wherein

the first antiferromagnetic layer is formed of at least one of IrMn and PtMn.

7. The magnetometric sensor according to claim 2 , wherein

the fixed magnetic layer includes a first magnetic sub-layer and a second magnetic sub-layer stacked with a nonmagnetic intermediate sub-layer interposed therebetween, the second magnetic sub-layer being in contact with the nonmagnetic material layer, wherein

the first magnetic sub-layer and the second magnetic sub-layer are self-pinned magnetic layers having magnetization fixed in mutually antiparallel directions.

8. The magnetometric sensor according to claim 2 , wherein

the fixed magnetic layer includes a second antiferromagnetic sub-layer on the opposite side to the side facing the nonmagnetic material layer and a ferromagnetic sub-layer to cause an exchange coupling bias between the second antiferromagnetic sub-layer and the ferromagnetic sub-layer and align the magnetization direction of the fixed magnetic layer in a prescribed direction.

9. The magnetometric sensor according to claim 2 , wherein

the layered structure has the free magnetic layer between the fixed magnetic layer and the substrate.

10. The magnetometric sensor according to claim 2 , wherein

the layered structure has the fix magnetic layer between the free magnetic layer and the substrate.

11. A current sensor comprising the magnetometric sensor according to claim 2 .

12. The magnetometric sensor according to claim 1 , wherein

the free magnetic layer includes:

a misfit-reducing sub-layer being in contact with the first antiferromagnetic layer and decreasing the lattice mismatch of the free magnetic layer with the first antiferromagnetic layer; and

a ferromagnetic sub-layer made of a ferromagnetic material disposed on the misfit-reducing sub-layer on the opposite side to the side facing the first antiferromagnetic layer.

13. The magnetometric sensor according to claim 12 , wherein

the misfit-reducing sub-layer and the ferromagnetic sub-layer each have a face-centered cubic (fcc) structure; and

the lattice spacing of the fcc(111) plane of the misfit-reducing sub-layer is larger than that of the fcc(111) plane of the ferromagnetic sub-layer.

14. The magnetometric sensor according to claim 12 , wherein

the misfit-reducing sub-layer contains at least one iron group element and at least one platinum group element.

15. A current sensor comprising the magnetometric sensor according to claim 12 .

16. A current sensor comprising the magnetometric sensor according to claim 1 .

17. A magnetometric sensor comprising:

a magnetoresistance effect element having a sensitivity axis in a specific direction, wherein

the magnetoresistance effect element includes:

a layered structure on a substrate, the layered structure comprising a fixed magnetic layer and a free magnetic layer stacked with a nonmagnetic material layer interposed therebetween; and

a first antiferromagnetic layer on the free magnetic layer on the opposite side to the side facing the nonmagnetic material layer to cause an exchange coupling bias between the first antiferromagnetic layer and the free magnetic layer and align the magnetization direction of the free magnetic layer in a prescribed direction in a state of permitting variation in magnetization, wherein

the free magnetic layer includes:

a first sub-layer serving as a misfit-reducing sub-layer for decreasing the lattice mismatch of the free magnetic layer with the first antiferromagnetic layer;

a first free magnetic sub-layer disposed between the first sub-layer and the nonmagnetic material layer; and

a second free magnetic sub-layer disposed between the first sub-layer and the first antiferromagnetic layer and ferromagnetically coupled to the first free magnetic sub-layer, wherein

the first sub-layer contains at least one selected from the group consisting of Pt, Pd, Ta, and W.

18. A current sensor comprising the magnetometric sensor according to claim 17 .

19. A magnetometric sensor comprising:

a magnetoresistance effect element having a sensitivity axis in a specific direction, wherein

the magnetoresistance effect element has a layered structure on a substrate, the layered structure comprising a fixed magnetic layer and a free magnetic layer stacked with a nonmagnetic material layer interposed therebetween;

the magnetoresistance effect element includes a first antiferromagnetic layer on the free magnetic layer on the opposite side to the side facing the nonmagnetic material layer to cause an exchange coupling bias between the first antiferromagnetic layer and the free magnetic layer and align the magnetization direction of the free magnetic layer in a prescribed direction in a state of permitting variation in magnetization;

the free magnetic layer includes:

a first sub-layer being in contact with the first antiferromagnetic layer and serving as a misfit-reducing sub-layer for decreasing the lattice mismatch of the free magnetic layer with the first antiferromagnetic layer; and

a ferromagnetic sub-layer made of a ferromagnetic material disposed on the first sub-layer on the opposite side to the side facing the first antiferromagnetic layer, wherein

the first sub-layer contains at least one iron group element and at least one platinum group element.

20. A current sensor comprising the magnetometric sensor according to claim 19 .