Double tunnel junction with magnetoresistance enhancement layer

Claim 2

A resonant enhanced double tunnel junction sensor that has an air bearing surface (ABS) comprising: an electrically conductive first shield layer; an electrically conductive first antiferromagnetic pinning layer that has a magnetic moment oriented in a first predetermined direction; an electrically conductive first ferromagnetic pinned layer exchange coupled to the first pinning layer so that a magnetic moment of the first pinned layer is pinned in the first predetermined direction; a first enhancement layer capable of enhancing spin polarized resonant tunneling; a first spacer layer; a ferromagnetic free layer that has a magnetic moment in a second predetermined direction, the second predetermined direction being different than the first direction, the magnetic moment being free to rotate relative to the second predetermined direction in response to an applied magnetic field; a second spacer layer; a second enhancement layer capable of enhancing spin polarized resonant tunneling; an electrically conductive second ferromagnetic pinned layer; an electrically conductive second antiferromagnetic pinning layer that has magnetic spins oriented in the first predetermined direction and by exchange coupling pins the magnetic moment of the second pinned layer in the first predetermined direction; and an electrically conductive second shield layer.

Claim 3

A resonant enhanced double tunnel junction sensor as claimed in claim 1 wherein the first and second shield layers are used for electrical leads.

Claim 4

A resonant enhanced double tunnel junction sensor as claimed in claim 1 wherein the electrically conductive first and second antiferromagnetic pinning layers have a thickness from 50 Å to 250 Å.

Claim 5

A resonant enhanced double tunnel junction sensor as claimed in claim wherein the conductive antiferromagnetic pinning layers are selected from the group PtMn, MnFe, NiMn, and IrMn.

Claim 6

A resonant enhanced double tunnel junction sensor as claimed in claim 1 wherein the electrically conductive first and second ferromagnetic pinned layers have a thickness from 20 Å to 60 Å.

Claim 7

A resonant enhanced double tunnel junction sensor as claimed in claim wherein the ferromagnetic pinned layers are selected from the group consisting of Co 90 Fe 10 , NiFe and Co.

Claim 8

A resonant enhanced double tunnel junction sensor as claimed in claim 1 wherein the first ferromagnetic pinned layer is an antiparallel (AP) pinned layer that includes: a ruthenium (Ru) film layer and first and second ferromagnetic pinned film layers; the ruthenium layer being located between the first pinned film layer and the second pinned film layer; the first pinned film layer exchange coupled to the first pinning layer so that a magnetic moment of the first pinned film layer is pinned in the first predetermined direction; and the second pinned film layer having a magnetic moment in a third direction, the third direction being antiparallel to the first direction.

Claim 9

A resonant enhanced double tunnel junction sensor as claimed in claim 7 wherein the first and second pinned film layers are made from cobalt (Co).

Claim 10

A resonant enhanced double tunnel junction sensor as claimed in claim 8 wherein the first and second pinned film layers have a thickness of 25 Å and 20 Å respectively and the ruthenium layer has a thickness of 8 Å.

Claim 11

A resonant enhanced double tunnel junction sensor as claimed in claim 7 wherein the second ferromagnetic pinned layer is an antiparallel (AP) pinned layer that includes: a ruthenium (Ru) film layer and third and forth ferromagnetic pinned film layers; the ruthenium layer being located between the third pinned film layer and the forth pinned film layer; the forth pinned film layer exchange coupled to the second pinning layer so that a magnetic moment of the forth pinned film layer is pinned in the first predetermined direction; and the third pinned film layer having a magnetic moment in a third direction, the third direction being antiparallel to the first direction.

Claim 12

A resonant enhanced double tunnel junction sensor as claimed in claim 10 wherein the third and forth pinned film layers are made from cobalt (Co).

Claim 13

A resonant enhanced double tunnel junction sensor as claimed in claim 11 wherein the third and forth pinned film layers have a thickness of 20 Å and 25 Å respectively and the ruthenium layer has a thickness of 8 Å.

Claim 14

A resonant enhanced double tunnel junction sensor as claimed in claim 1 wherein the first and second enhancement layers have a thickness of 10 Å.

Claim 15

A resonant enhanced double tunnel junction sensor as claimed in claim 13 wherein the enhancement layers are made from Cu or Al.

Claim 16

A resonant enhanced double tunnel junction sensor as claimed in claim 1 wherein the first and second spacer layers have a thickness from 10 Å to 30 Å.

Claim 17

A resonant enhanced double tunnel junction sensor as claimed in claim 15 wherein the spacer layers are made from aluminum oxide.

Claim 18

A resonant enhanced double tunnel junction sensor as claimed in claim 1 wherein the ferromagnetic alloy free layer has a thickness from 30 Å to 100 Å.

Claim 19

A resonant enhanced double tunnel junction sensor as claimed in claim 17 wherein the ferromagnetic alloy free layer is made from NiFe.

Claim 20

A resonant enhanced double tunnel junction sensor as claimed in claim 17 wherein the ferromagnetic alloy free layer is made from a combination of 25% Co 90 Fe 10 and 75% NiFe.

Claim 21

A resonant enhanced double tunnel junction sensor as claimed in claim 1 wherein the first and second shields are made from Permalloy (Ni 80 Fe 20 ).

Claim 22

A resonant enhanced double tunnel junction sensor as claimed in claim 1 wherein the first predetermined direction being normal to the ABS.

Claim 23

A magnetic head that has an air bearing surface (ABS) comprising: a read head that includes: a resonant enhanced double tunnel junction sensor responsive to applied magnetic fields; first and second electrically conductive lead layers connected to the double tunnel junction sensor for conducting a tunnel current through the double tunnel junction sensor; the double tunnel junction sensor including: an electrically conductive first shield layer; an electrically conductive first antiferromagnetic pinning layer that has magnetic spins oriented in a first predetermined direction; an electrically conductive first ferromagnetic pinned layer exchange coupled to the first pinning layer so that a magnetic moment of the first pinned layer is pinned in the first predetermined direction; a first enhancement layer capable of enhancing spin polarized resonant tunneling; a first spacer layer; a ferromagnetic free layer that has a magnetic moment in a second predetermined direction, the second predetermined direction being different than the first direction, the magnetic moment being free to rotate relative to the second predetermined direction in response to an applied magnetic field; a second spacer layer; a second enhancement layer capable of enhancing spin polarized resonant tunneling; an electrically conductive second ferromagnetic pinned layer; an electrically conductive second antiferromagnetic pinning layer that has magnetic spins oriented in the first predetermined direction and by exchange coupling pins the magnetic moment of the second pinned layer in the first predetermined direction; and an electrically conductive second shield layer; a write head including: first and second pole piece layers and a write gap layer; the first and second pole piece layers being separated by the write gap layer at the ABS and connected at a back gap that is recessed rearwardly in the head from the ABS; an insulation stack having at least first and second insulation layers; at least one coil layer embedded in the insulation stack; and the insulation stack and the at least one coil layer being located between the first and second pole piece layers.

Claim 24

A magnetic head that has an air bearing surface (ABS) comprising: a read head that includes: a resonant enhanced double tunnel junction sensor responsive to applied magnetic fields; first and second electrically conductive lead layers connected to the double tunnel junction sensor for conducting a tunnel current through the double tunnel junction sensor; the double tunnel junction sensor including: an electrically conductive first shield layer; an electrically conductive first antiferromagnetic pinning layer that has magnetic spins oriented in a first predetermined direction; an electrically conductive first ferromagnetic pinned layer exchange coupled to the first pinning layer so that a magnetic moment of the first pinned layer is pinned in the first predetermined direction; a first enhancement layer capable of enhancing spin polarized resonant tunneling; a first spacer layer; a ferromagnetic free layer that has a magnetic moment in a second predetermined direction, the second predetermined direction being different than the first direction, the magnetic moment being free to rotate relative to the second predetermined direction in response to an applied magnetic field; a second spacer layer; a second enhancement layer capable of enhancing spin polarized resonant tunneling; an electrically conductive second ferromagnetic pinned layer; an electrically conductive second antiferromagnetic pinning layer that has magnetic spins oriented in the first predetermined direction and by exchange coupling pins the magnetic moment of the second pinned layer in the first predetermined direction; and an electrically conductive second shield layer; a write head including: first and second pole piece layers and a write gap layer; the first and second pole piece layers being separated by the write gap layer at the ABS and connected at a back gap that is recessed rearwardly in the head from the ABS; an insulation stack having at least first and second insulation layers; at least one coil layer embedded in the insulation stack; and the insulation stack and the at least one coil layer being located between the first and second pole piece layers.

Claim 25

A magnetic head as claimed in claim 22 wherein the first and second electrically conductive lead layers are the electrically conductive first and second shield layers.

Claim 26

A magnetic head as claimed in claim 22 wherein the electrically conductive first and second antiferromagnetic pinning layers have a thickness from 50 Å to 250 Å.

Claim 27

A magnetic head as claimed in claim 24 wherein the conductive antiferromagnetic pinning layers are selected from the group PtMn, MnFe, NiMn, and IrMn.

Claim 28

A magnetic head as claimed in claim 22 wherein the electrically conductive first and second ferromagnetic pinned layers have a thickness from 20 Å to 60 Å.

Claim 29

A magnetic head as claimed in claim 26 wherein the ferromagnetic pinned layers are selected from the group consisting of Co 90 Fe 10 , NiFe and Co.

Claim 30

A magnetic head as claimed in claim 22 wherein the first ferromagnetic pinned layer is an antiparallel (AP) pinned layer that includes: a ruthenium (Ru) film layer and first and second ferromagnetic pinned film layers; the ruthenium layer being located between the first pinned film layer and the second pinned film layer; the first pinned film layer exchange coupled to the first pinning layer so that a magnetic moment of the first pinned film layer is pinned in the first predetermined direction; and the second pinned film layer having a magnetic moment in a third direction, the third direction being antiparallel to the first direction.

Claim 31

A magnetic head as claimed in claim 28 wherein the first and second pinned film layers are made from cobalt (Co).

Claim 32

A magnetic head as claimed in claim 29 wherein the first and second pinned film layers have a thickness of 25 Å and 20 Å respectively and the ruthenium layer has a thickness of 8 Å.

Claim 33

A magnetic head as claimed in claim 28 wherein the second ferromagnetic pinned layer is an antiparallel (AP) pinned layer that includes: a ruthenium (Ru) film layer and third and forth ferromagnetic pinned film layers; the ruthenium layer being located between the third pinned film layer and the forth pinned film layer; the forth pinned film layer exchange coupled to the second pinning layer so that a magnetic moment of the forth pinned film layer is pinned in the first predetermined direction; and the third pinned film layer having a magnetic moment in a third direction, the third direction being antiparallel to the first direction.

Claim 34

A magnetic head as claimed in claim 31 wherein the third and forth pinned film layers are made from cobalt (Co).

Claim 35

A magnetic head as claimed in claim 32 wherein the third and forth pinned film layers have a thickness of 20 Å and 25 Å respectively and the ruthenium layer has a thickness of 8 Å.

Claim 36

A magnetic head as claimed in claim 22 wherein the first and second enhancement layers have a thickness of 10 Å.

Claim 37

A magnetic head as claimed in claim 34 wherein the enhancement layers are made from Cu or Al.

Claim 38

A magnetic head as claimed in claim 22 wherein the first and second spacer layers have a thickness from 10 Å to 30 Å.

Claim 39

A magnetic head as claimed in claim 36 wherein the spacer layers are made from aluminum oxide.

Claim 40

A magnetic head as claimed in claim 22 wherein the ferromagnetic alloy free layer has a thickness from 30 Å to 100 Å.

Claim 41

A magnetic head as claimed in claim 38 wherein the ferromagnetic alloy free layer is made from NiFe.

Claim 42

A magnetic head as claimed in claim 38 wherein the ferromagnetic alloy free layer is made from a combination of 25% Co 90 Fe 10 and 75% NiFe.

Claim 43

A magnetic head as claimed in claim 22 wherein the first and second shields are made from Permalloy (Ni 80 Fe 20 ).

Claim 44

A magnetic head as claimed in claim 22 wherein the first predetermined direction being normal to the ABS.

Claim 45

A magnetic disk drive, comprising: the magnetic head including a combined read head and write head, said magnetic head having an air bearing surface (ABS); the read head including: a resonant enhanced double tunnel junction sensor responsive to applied magnetic fields; and first and second electrically conductive lead layers connected to the double tunnel junction sensor for conducting a tunnel current through the double tunnel junction sensor; the double tunnel junction sensor including: an electrically conductive first shield layer; an electrically conductive first antiferromagnetic pinning layer that has magnetic spins oriented in a first predetermined direction; an electrically conductive first ferromagnetic pinned layer exchange coupled to the first pinning layer so that a magnetic moment of the first pinned layer is pinned in the first predetermined direction; a first enhancement layer capable of enhancing spin polarized resonant tunneling; a first spacer layer; a ferromagnetic free layer that has a magnetic moment in a second predetermined direction, the second predetermined direction being different than the first direction, the magnetic moment being free to rotate relative to the second predetermined direction in response to an applied magnetic field; a second spacer layer; a second enhancement layer capable of enhancing spin polarized resonant tunneling; an electrically conductive second ferromagnetic pinned layer; an electrically conductive second antiferromagnetic pinning layer that has magnetic spins oriented in the first predetermined direction and by exchange coupling pins the magnetic moment of the second pinned layer in the first predetermined direction; and an electrically conductive second shield layer; the write head including: first and second pole piece layers and a write gap layer wherein the first pole piece layer and the second shield layer are a common layer; the first and second pole piece layers being separated by the write gap layer at the ABS and connected at a back gap that is recessed rearwardly in the head from the ABS; an insulation stack having at least first and second insulation layers; at least one coil layer embedded in the insulation stack; and the insulation stack and the at least one coil layer being located between the first and second pole piece layers; a frame; a magnetic disk rotatably supported on the frame; a support mounted on the frame for supporting the magnetic head with its ABS facing the magnetic disk so that the magnetic head is in a transducing relationship with the magnetic disk; means for rotating the magnetic disk; positioning means connected to the support for moving the magnetic head to multiple positions with respect to said magnetic disk; and processing means connected to the magnetic head, to the means for rotating the magnetic disk and to the positioning means for exchanging signals with the merged magnetic head, for controlling movement of the magnetic disk and for controlling the position of the magnetic head.

Claim 46

A magnetic disk drive, comprising: the magnetic head including a combined read head and write head, said magnetic head having an air bearing surface (ABS); the read head including: a resonant enhanced double tunnel junction sensor responsive to applied magnetic fields; and first and second electrically conductive lead layers connected to the double tunnel junction sensor for conducting a tunnel current through the double tunnel junction sensor; the double tunnel junction sensor including: an electrically conductive first shield layer; an electrically conductive first antiferromagnetic pinning layer that has magnetic spins oriented in a first predetermined direction; an electrically conductive first ferromagnetic pinned layer exchange coupled to the first pinning layer so that a magnetic moment of the first pinned layer is pinned in the first predetermined direction; a first enhancement layer capable of enhancing spin polarized resonant tunneling; a first spacer layer; a ferromagnetic free layer that has a magnetic moment in a second predetermined direction, the second predetermined direction being different than the first direction, the magnetic moment being free to rotate relative to the second predetermined direction in response to an applied magnetic field; a second spacer layer; a second enhancement layer capable of enhancing spin polarized resonant tunneling; an electrically conductive second ferromagnetic pinned layer; an electrically conductive second antiferromagnetic pinning layer that has magnetic spins oriented in the first predetermined direction and by exchange coupling pins the magnetic moment of the second pinned layer in the first predetermined direction; and an electrically conductive second shield layer; the write head including: first and second pole piece layers and a write gap layer wherein the first pole piece layer and the second shield layer are a common layer; the first and second pole piece layers being separated by the write gap layer at the ABS and connected at a back gap that is recessed rearwardly in the head from the ABS; an insulation stack having at least first and second insulation layers; at least one coil layer embedded in the insulation stack; and the insulation stack and the at least one coil layer being located between the first and second pole piece layers; a frame; a magnetic disk rotatably supported on the frame; a support mounted on the frame for supporting the magnetic head with its ABS facing the magnetic disk so that the magnetic head is in a transducing relationship with the magnetic disk; means for rotating the magnetic disk; positioning means connected to the support for moving the magnetic head to multiple positions with respect to said magnetic disk; and processing means connected to the magnetic head, to the means for rotating the magnetic disk and to the positioning means for exchanging signals with the merged magnetic head, for controlling movement of the magnetic disk and for controlling the position of the magnetic head.

Claim 47

A magnetic disk drive as claimed in claim 43 wherein the processing means is connected to the first and second leads for applying the tunnel current to the sensor.

Claim 48

A magnetic disk drive as claimed in claim 44 wherein the processing means applies said tunnel current.

Claim 49

A magnetic disk drive as claimed in claim 43 wherein the first and second electrically conductive lead layers are the electrically conductive first and second shield layers.

Claim 50

A magnetic disk drive as claimed in claim 43 wherein the electrically conductive first and second antiferromagnetic pinning layers have a thickness from 50 Å to 250 Å.

Claim 51

A magnetic disk drive as claimed in claim 47 wherein the conductive antiferromagnetic pinning layers are selected from the group PtMn, MnFe, NiMn, and IrMn.

Claim 52

A magnetic disk drive as claimed in claim 43 wherein the electrically conductive first and second ferromagnetic pinned layers have a thickness from 20 Å to 60 Å.

Claim 53

A magnetic disk drive as claimed in claim 49 wherein the ferromagnetic pinned layers are selected from the group consisting of Co 90 Fe 10 , NiFe and Co.

Claim 54

A magnetic disk drive as claimed in claim 43 wherein the first ferromagnetic pinned layer is an antiparallel (AP) pinned layer that includes: a ruthenium (Ru) film layer and first and second ferromagnetic pinned film layers; the ruthenium layer being located between the first pinned film layer and the second pinned film layer; the first pinned film layer exchange coupled to the first pinning layer so that a magnetic moment of the first pinned film layer is pinned in the first predetermined direction; and the second pinned film layer having a magnetic moment in a third direction, the third direction being antiparallel to the first direction.

Claim 55

A magnetic disk drive as claimed in claim 51 wherein the first and second pinned film layers are made from cobalt (Co).

Claim 56

A magnetic disk drive as claimed in claim 52 wherein the first and second pinned film layers have a thickness of 25 Å and 20 Å respectively and the ruthenium layer has a thickness of 8 Å.

Claim 57

A magnetic disk drive as claimed in claim 51 wherein the second ferromagnetic pinned layer is an antiparallel (AP) pinned layer that includes: a ruthenium (Ru) film layer and third and forth ferromagnetic pinned film layers; the ruthenium layer being located between the third pinned film layer and the forth pinned film layer; the forth pinned film layer exchange coupled to the second pinning layer so that a magnetic moment of the forth pinned film layer is pinned in the first predetermined direction; and the third pinned film layer having a magnetic moment in a third direction, the third direction being antiparallel to the first direction.

Claim 58

A magnetic disk drive as claimed in claim 54 wherein the third and forth pinned film layers are made from cobalt (Co).

Claim 59

A magnetic disk drive as claimed in claim 55 wherein the third and forth pinned film layers have a thickness of 20 Å and 25 Å respectively and the ruthenium layer has a thickness of 8 Å.

Claim 60

A magnetic disk drive as claimed in claim 43 wherein the first and second enhancement layers have a thickness of 10 Å.

Claim 61

A magnetic disk drive as claimed in claim 57 wherein the enhancement layers are made from Cu or Al.

Claim 62

A magnetic disk drive as claimed in claim 43 wherein the first and second spacer layers have a thickness from 10 Å to 30 Å.

Claim 63

A magnetic disk drive as claimed in claim 59 wherein the spacer layers are made from aluminum oxide.

Claim 64

A magnetic disk drive as claimed in claim 43 wherein the ferromagnetic alloy free layer has a thickness from 30 Å to 100 Å.

Claim 65

A magnetic disk drive as claimed in claim 61 wherein the ferromagnetic alloy free layer is made from NiFe.

Claim 66

A magnetic disk drive as claimed in claim 61 wherein the ferromagnetic alloy free layer is made from a combination of 25% Co 90 Fe 10 and 75% NiFe.

Claim 67

A magnetic disk drive as claimed in claim 43 wherein the first and second shields are made from Permalloy (Ni 80 Fe 20 ).

Claim 68

A magnetic disk drive as claimed in claim 43 wherein the first predetermined direction being normal to the ABS.