CPP-type thin film magnetic head provided with side shields including a pair of antimagnetically exchanged-coupled side shield magnetic layers
A thin film magnetic head includes a magnetoresistive (MR) stack disposed between first and second shield layers in a direction orthogonal to the film surface; a first exchange-coupling layer that is positioned between the MR stack and the first shield layer; a second exchange-coupling layer that is positioned between the MR stack and the second shield layer; a bias magnetic field application layer that is disposed at an opposite surface of the MR stack from an air bearing surface (ABS); and pair of side shield layers that are positioned at both sides of the MR stack with respect to a track width direction. Each of the side shield layers includes a pair of magnetic layers that are antiferromagnetically exchange-coupled through a side shield ruthenium layer.
1. A thin film magnetic head comprising:
a magnetoresistive (MR) stack having first and second magnetoresistive (MR) magnetic layers whose magnetization directions change according to an external magnetic field, and a nonmagnetic intermediate layer disposed between and with contacting the first and second MR magnetic layers;
first and second shield layers that function as electrodes supplying a sense current to the MR stack in a current perpendicular to plate (CPP) direction, the first and second shield layers being disposed on a first side and on a second side of the MR stack, respectively, as seen in the CPP direction, wherein
the first shield layer faces the first MR magnetic layer, and has a first magnetic control layer disposed at a surface where the first shield layer faces the first MR magnetic layer, the first magnetic control layer having a magnetization direction fixed to a first direction that is parallel to an air bearing surface (ABS);
the second shield layer faces the second MR magnetic layer, and has a second magnetic control layer disposed at a surface where the second shield layer faces the second MR magnetic layer, the second magnetic control layer having a magnetization direction fixed to another direction that is antiparallel to the first direction;
a first exchange-coupling layer that is positioned between the first MR magnetic layer and the first magnetic control layer, and that generates an exchange-coupling between the first MR magnetic layer and the first magnetic control layer;
a second exchange-coupling layer that is positioned between the second MR magnetic layer and the second magnetic control layer, and that generates an exchange-coupling between the second MR magnetic layer and the second magnetic control layer;
a bias magnetic field application layer that is disposed at a surface of the MR stack, the surface being on a back side of the MR stack, as seen from and in a direction perpendicular to the ABS, and that applies a bias magnetic field to the MR stack in a direction orthogonal to the ABS; and
a pair of side shield layers that are positioned on a third side and on a fourth side of the MR stack, respectively, as seen in a track width direction, wherein
each of the side shield layers includes a pair of side shield magnetic layers that are antimagnetically exchange-coupled through a side shield ruthenium layer.
2. The thin film magnetic head according to claim 1 , wherein the side shield magnetic layers directly contact each other in a vicinity of the MR stack where the side shield ruthenium layer is not present.
3. The thin film magnetic head according to claim 1 , wherein the each of the side shield magnetic layers includes a soft magnetic layer and a CoFe layer that contacts the side shield ruthenium layer.
4. The thin film magnetic head according to claim 1 , wherein the soft magnetic layer is either a NiFe layer or a CoZrTa layer.
5. The thin film magnetic head according to claim 1 , wherein the first and second exchange-coupling layers are configured with a ruthenium layer of 0.8 nm in a film thickness.
6. The thin film magnetic head according to claim 1 , wherein the first and second exchange-coupling layers are magnetic layers that are configured with a plurality of layers and that include at least a ruthenium layer of 0.8 nm in a film thickness among the plurality of layers.
7. The thin film magnetic head according to claim 1 , wherein
the first shield layer includes a first antiferromagnetic layer, an intermediate magnetic layer that is exchange-coupled with the first antiferromagnetic layer, and a ruthenium layer that is positioned between the intermediate magnetic layer and the first magnetic control layer and that exchange-couples the intermediate magnetic layer with the first magnetic control layer, and
the second shield layer includes a second antiferromagnetic layer that is exchange-coupled with the second magnetic control layer.
8. A slider equipped with the thin film magnetic head according to claim 1 .
9. A head gimbal assembly comprising
the slider according to claim 8 and
a suspension that elastically supports the slider.
10. A hard disk device comprising
the slider according claim 8 and
a device that supports the slider and positions the slider with respect to a recording medium.
11. A wafer on which a laminated structure is formed, the laminated structure being configured as the thin film magnetic head according to claim 1 .
12. A thin film magnetic head comprising:
a magnetoresistive (MR) stack having first and second magnetoresistive (MR) magnetic layers whose magnetization directions change according to an external magnetic field, and a nonmagnetic intermediate layer disposed between and with contacting the first and second MR magnetic layers;
first and second shield layers that function as electrodes supplying a sense current to the MR stack in a direction orthogonal to a laminating direction of the MR stack, the MR stack being disposed between the first shield layer and the second shield layer in the direction orthogonal to the laminating direction, wherein
the first shield layer faces the first MR magnetic layer, and has a first magnetic control layer disposed at a surface where the first shield layer faces the first MR magnetic layer, the first magnetic control layer having a magnetization direction fixed to a first direction that is parallel to an air bearing surface (ABS);
the second shield layer faces the second MR magnetic layer, and has a second magnetic control layer disposed at a surface where the second shield layer faces the second MR magnetic layer, the second magnetic control layer having a magnetization direction fixed to another direction that is antiparallel to the first direction;
a first exchange-coupling layer that is positioned between the first MR magnetic layer and the first magnetic control layer, and that generates an exchange-coupling between the first MR magnetic layer and the first magnetic control layer;
a second exchange-coupling layer that is positioned between the second MR magnetic layer and the second magnetic control layer, and that generates an exchange-coupling between the second MR magnetic layer and the second magnetic control layer;
a bias magnetic field application layer that is disposed at an opposite surface of the MR stack from the ABS, and that applies a bias magnetic field to the MR stack in a direction orthogonal to the ABS; and
a pair of side shield layers that are positioned at both sides of the MR stack with respect to a track width direction, wherein
each of the side shield layers includes a pair of side shield magnetic layers that are antimagnetically exchange-coupled through a side shield ruthenium layer,
the first shield layer includes a first antiferromagnetic layer, an intermediate magnetic layer that is exchange-coupled with the first antiferromagnetic layer, and a ruthenium layer that is positioned between the intermediate magnetic layer and the first magnetic control layer and that exchange-couples the intermediate magnetic layer with the first magnetic control layer, and
the second shield layer includes a second antiferromagnetic layer that is exchange-coupled with the second magnetic control layer.