Microwave assisted magnetic recording head and magnetic data storage apparatus
To suppress a spread of not only a recording magnetic field generated from a main pole but also a high-frequency magnetic field generated from a spin torque oscillator in a microwave assisted magnetic recording head. The main pole and the spin torque oscillator are surrounded by a trailing shield layer and are also surrounded by a side/leading shield layer with an insulator sidegap layer interposed therebetween, and a high-frequency magnetic field shield layer, which absorbs a high-frequency magnetic field generated from the spin torque oscillator, is arranged in at least part of the shield layers.
1. A magnetic head comprising:
a main pole configured to generate a recording magnetic field;
a spin torque oscillator arranged around the main pole and configured to generate a high-frequency magnetic field; and
a shield layer arranged in a manner surrounding the main pole and the spin torque oscillator, wherein
the shield layer partially includes a high-frequency magnetic field shield layer, the high-frequency magnetic field shield layer including a material that absorbs the high-frequency magnetic field;
the high-frequency magnetic field shield layer includes a magnetic layer with a stacked structure of soft magnetic material layers that are stacked with a spacer interposed therebetween, and a permeability of the stacked structure becomes zero at a frequency greater than or equal to 11 GHz.
2. The magnetic head according to claim 1 , wherein the soft magnetic material is one of Fe, Co, a Fe—Co-based alloy, a Fe—Ni—based alloy, or a Fe—Co—Ni—based alloy, and the spacer is one of Ru, Ir, Rh, Re, Cu, Cr, or an alloy thereof.
3. The magnetic head according to claim 1 , wherein the high-frequency magnetic field shield layer is arranged on track width sides with respect to the spin torque oscillator.
4. The magnetic head according to claim 1 , wherein the high-frequency magnetic field shield layer is arranged on a trailing side with respect to the spin torque oscillator.
5. The magnetic head according to claim 1 , further comprising:
a read sensor for reading information recorded on a magnetic disk medium, wherein the high-frequency magnetic field shield layer is arranged between the spin torque oscillator and the read sensor.
6. The magnetic head according to claim 1 , wherein a thickness of the magnetic layer with the stacked structure of soft magnetic material layers is less than or equal to 35 nm.
7. A magnetic data storage apparatus comprising:
a magnetic disk medium;
a disk driving unit configured to drive the magnetic disk medium;
a magnetic head configured to perform recording and reading operations on the magnetic disk medium; and
a head driving unit configured to move the magnetic head to a desired position above the magnetic disk medium, wherein
the magnetic head includes
a main pole configured to generate a recording magnetic field for recording information as a magnetic signal on the magnetic disk medium,
a spin torque oscillator arranged around the main pole and configured to generate a high-frequency magnetic field for enhancing a precession motion of magnetization of the magnetic disk medium,
a shield layer arranged in a manner surrounding the main pole and the spin torque oscillator, and
a read sensor for reading information recorded on the magnetic disk medium,
the shield layer partially includes a high-frequency magnetic field shield layer including a material that absorbs the high-frequency magnetic field,
the high-frequency magnetic field shield layer includes a magnetic layer with a stacked structure of soft magnetic material layers that are stacked with a spacer interposed therebetween, and a permeability of the stacked structure becomes zero at a frequency greater than or equal to 11 GHz: and
an effective anisotropy field of the high-frequency magnetic field shield layer is higher than an effective anisotropy field of a layer, which responds to a high-frequency magnetic field, of the magnetic disk medium.
8. The magnetic data storage apparatus according to claim 7 , wherein the high-frequency magnetic field shield layer is arranged on track width sides with respect to the spin torque oscillator.
9. The magnetic data storage apparatus according to claim 7 , wherein the high-frequency magnetic field shield layer is arranged on a trailing side with respect to the spin torque oscillator.
10. The magnetic data storage apparatus according to claim 7 , wherein the high-frequency magnetic field shield layer is arranged between the spin torque oscillator and the read sensor.