Pinned shield with controllable exchange bias field
The present disclosure generally relates to a two-dimensional magnetic recording (TDMR) read head. The TDMR read head comprises a first sensor, a second sensor, and a middle shield (MS) disposed between the first and second sensors. The MS comprises a seed layer, an IrMn layer disposed on the seed layer, an insertion layer comprising Ru or CoFe disposed on the IrMn layer, a first NiFe layer having a pinned magnetization, and a cap layer disposed over the first NiFe layer. In one embodiment, the MS further comprises an Ru layer disposed on the first NiFe layer and a second NiFe layer disposed on the Ru layer, the second NiFe layer having a pinned magnetization in a direction antiparallel to the first NiFe layer. The insertion layer comprising Ru decreases an exchange energy of the MS. The insertion layer comprising CoFe increases an exchange energy of the MS.
1. A two dimensional magnetic recording (TDMR) read head, comprising:
a first read sensor comprising a first lower shield, the first lower shield comprising:
a first seed layer;
an IrMn layer disposed on the first seed layer;
a first insertion layer disposed on the IrMn layer, the first insertion layer comprising Ru or CoFe; and
a first NiFe layer disposed on the first insertion layer, the first NiFe layer having a pinned magnetization in a first direction; and
a second read sensor disposed over the first read sensor; and
a middle shield disposed between the first read sensor and the second read sensor, the middle shield comprising:
a second seed layer;
an antiferromagnetic layer disposed on the second seed layer, the antiferromagnetic layer comprising IrMn, PtMn, NiMn, FeMn, IrMnCr, or combinations thereof;
a second insertion layer disposed on the antiferromagnetic layer, the second insertion layer comprising Ru or CoFe; and
a ferromagnetic layer disposed on the second insertion layer, the ferromagnetic layer comprising NiFe or NiCoFe.
2. The TDMR read head of claim 1 , wherein the second insertion layer comprises Ru, and wherein an exchange energy of the middle shield is between about 0.05 erg/cm 2 to about 0.25 erg/cm 2 .
3. The TDMR read head of claim 1 , wherein the second insertion layer comprises CoFe, and wherein an exchange energy of the middle shield is between about 0.35 erg/cm 2 to about 0.45 erg/cm 2 .
4. The TDMR read head of claim 1 , wherein the ferromagnetic layer of the middle shield has a pinned magnetization direction.
5. The TDMR read head of claim 1 , wherein the first read sensor and the second read sensor each individually comprises a first free layer and a second free layer, and wherein the middle shield further comprises a cap layer disposed on the ferromagnetic layer.
6. The TDMR read head of claim 1 , wherein the second insertion layer has a thickness of about 1 Å to about 15 Å.
7. A magnetic recording device comprising the TDMR read head of claim 1 .
8. A two dimensional magnetic recording (TDMR) read head, comprising:
a first read sensor;
a second read sensor disposed over the first read sensor; and
a middle shield disposed between the first read sensor and the second read sensor, the middle shield comprising:
a seed layer;
an antiferromagnetic layer disposed on the seed layer, the antiferromagnetic layer comprising IrMn, PtMn, NiMn, FeMn, IrMnCr, or combinations thereof;
an insertion layer disposed on and in contact with the antiferromagnetic layer, the insertion layer comprising Ru or CoFe;
a first NiFe or NiCoFe layer disposed on and in contact with the insertion layer, the first NiFe or NiCoFe layer having a pinned magnetization in a first direction;
a Ru, Rh, or Ir layer disposed on the first NiFe or NiCoFe layer;
a second NiFe or NiCoFe layer disposed on the Ru, Rh, or Ir layer, the second NiFe or NiCoFe layer having a pinned magnetization in a second direction antiparallel to the first direction; and
a cap layer disposed on the second NiFe or NiCoFe layer.
9. The TDMR read head of claim 8 , wherein the insertion layer comprises Ru and has a thickness of about 1 Å to about 4 Å.
10. The TDMR read head of claim 8 , wherein the insertion layer comprises CoFe and has a thickness of about 5 Å to about 15 Å.
11. The TDMR read head of claim 8 , wherein the first read sensor and the second read sensor are each individually dual free layer read sensors.
12. The TDMR read head of claim 8 , wherein the middle shield has a total thickness of about 2 μm, and wherein the middle shield has an exchange energy between about 0.05 erg/cm 2 to about 0.45 erg/cm 2 .
13. The TDMR read head of claim 8 , wherein when the insertion layer comprises Ru, the insertion layer has a thickness of about 1 Å to about 4 Å, and wherein when the insertion layer comprises CoFe, the insertion layer has a thickness of about 5 Å to about 15 Å.
14. A magnetic recording device comprising the TDMR read head of claim 8 .
15. A two dimensional magnetic recording (TDMR) read head, comprising:
a first lower shield;
a first dual free layer (DFL) read sensor disposed over the first lower shield;
a first upper shield disposed over the first DFL read sensor;
a middle shield disposed over the first upper shield, the middle shield comprising:
a seed layer comprising Ta and Ru;
an IrMn layer disposed on the seed layer;
an insertion layer disposed on the IrMn layer, the insertion layer comprising Ru or CoFe;
a first NiFe layer disposed on the insertion layer, the first NiFe layer having a pinned magnetization in a first direction;
a Ru, Rh, or Ir layer disposed on the first NiFe layer;
a second NiFe layer disposed on the Ru, Rh, or Ir layer, the second NiFe layer having a pinned magnetization in a second direction antiparallel to the first direction; and
a cap layer disposed over the second NiFe layer;
a second DFL read sensor disposed over the middle shield; and
a second upper shield disposed over the second DFL read sensor.
16. The TDMR read head of claim 15 , wherein when the insertion layer comprises Ru, the insertion layer has a thickness of about 1 Å to about 4 Å, and wherein when the insertion layer comprises CoFe, the insertion layer has a thickness of about 5 Å to about 15 Å.
17. The TDMR read head of claim 15 , wherein the first lower shield comprises:
a second seed layer;
a second IrMn layer disposed on the second seed layer;
a second insertion layer disposed on the second IrMn layer, the second insertion layer comprising Ru or CoFe;
a second NiFe layer disposed on the second insertion layer, the second NiFe layer having a pinned magnetization in the first direction; and
a second cap layer disposed over the second NiFe layer.
18. The TDMR read head of claim 17 , wherein the first lower shield further comprises:
a second Ru, Rh, or Ir layer disposed on the second NiFe layer; and
a third NiFe layer disposed on the second Ru, Rh, or Ir layer, the third NiFe layer having a pinned magnetization in the second direction.
19. The TDMR read head of claim 15 , further comprising an insulating layer disposed between the first upper shield and the middle shield.
20. A magnetic recording device comprising the TDMR read head of claim 15 .