Perpendicular magnetic recording write head and system with improved spin torque oscillator for microwave-assisted magnetic recording
First Claim
1. A microwave-assisted magnetic recording (MAMR) write head for magnetizing regions in a perpendicular magnetic recording layer, the write head comprising:
- a write pole;
an electrically conductive coil coupled to the write pole, the write pole generating a magnetic write field in the presence of electrical write current through the coil;
a trailing shield of magnetically permeable material for altering the angle of the write field; and
a spin torque oscillator (STO) between the write pole and the trailing shield and comprising a ferromagnetic polarizer, a free ferromagnetic layer having a magnetization that rotationally oscillates in the presence of an electrical current through the free layer to thereby generate an oscillating magnetic field to assist the magnetic field from the write pole, and a nonmagnetic electrically conductive spacer between the polarizer and free layer, the polarizer having a magnetization, in the presence of the write field from the write pole, oriented at an angle greater than 20 degrees and less than 80 degrees from the normal to the plane parallel to the free layer.
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Abstract
A microwave-assisted magnetic recording (MAMR) write head and system has a spin-torque oscillator (STO) located between the write pole of the write head and a trailing shield that alters the write field from the write pole. The STO is a stack of layers whose planes lie generally parallel to the X-Y plane of an X-Y-Z coordinate system, the stack including a ferromagnetic polarizer layer, a free ferromagnetic layer, and a nonmagnetic electrically conductive spacer between the polarizer layer and the free layer. In the presence of the write field from the write pole the polarizer layer has its magnetization oriented at an angle between 20 and 80 degrees, preferably between 30 and 70 degrees, with the Z-axis. In the presence of a direct electrical current through the STO stack, the free layer magnetization rotates or precesses about the Z-axis with a non-zero angle to the Z-axis.
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Citations
27 Claims
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1. A microwave-assisted magnetic recording (MAMR) write head for magnetizing regions in a perpendicular magnetic recording layer, the write head comprising:
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a write pole; an electrically conductive coil coupled to the write pole, the write pole generating a magnetic write field in the presence of electrical write current through the coil; a trailing shield of magnetically permeable material for altering the angle of the write field; and a spin torque oscillator (STO) between the write pole and the trailing shield and comprising a ferromagnetic polarizer, a free ferromagnetic layer having a magnetization that rotationally oscillates in the presence of an electrical current through the free layer to thereby generate an oscillating magnetic field to assist the magnetic field from the write pole, and a nonmagnetic electrically conductive spacer between the polarizer and free layer, the polarizer having a magnetization, in the presence of the write field from the write pole, oriented at an angle greater than 20 degrees and less than 80 degrees from the normal to the plane parallel to the free layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A magnetic recording disk drive perpendicular recording write head for magnetizing regions in data tracks of a perpendicular magnetic recording layer on the disk, the head being formed on a slider having an air-bearing surface (ABS) lying substantially in a plane parallel to the X-Z plane of an X-Y-Z coordinate system and comprising:
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a substrate; a write pole on the substrate and aligned generally parallel to the Y-axis, the write pole having an end substantially at the ABS; an electrically conductive coil coupled to the write pole, the write pole generating a magnetic write field in the presence of electrical write current through the coil; a trailing shield on the substrate and formed of magnetically permeable material for altering the angle of the write field, the trailing shield being spaced from the write pole along the Z-axis; a spin torque oscillator (STO) on the substrate between the write pole and the trailing shield and comprising a stack of layers with planes generally parallel with the X-Y plane, said stack including a ferromagnetic polarizer layer having a magnetization, in the presence of the write field from the write pole, oriented at an angle φ
p between 20 degrees and 80 degrees from the Z-axis, a free ferromagnetic layer having a magnetization oriented at a non-zero angle ψ
to the Z-axis and free to rotate about the Z-axis in the presence of electrical current through the free layer, and a nonmagnetic electrically conductive spacer between the polarizer layer and the free layer; andcircuitry coupled to the STO and capable of supplying direct current through the stack when write current is supplied to the coil. - View Dependent Claims (18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification