Extended Spin Torque Oscillator for High-Density Magnetic Recording
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Solution Overview
Problem
High-density magnetic recording faces challenges due to thermal fluctuations, which cause signal degradation in magnetic recording media, especially as the volume of magnetocrystalline particles decreases, making it difficult to maintain magnetization reversal with conventional magnetic heads.
Innovation Solution
A microwave-assisted magnetic recording head with an extended spin torque oscillator is used, comprising a first non-magnetic spin scatterer, a reference layer, non-magnetic spin transfer layers, and magnetic field generating layers, where the drive current flows from the thicker magnetic field generating layer to the thinner one, enhancing the high-frequency magnetic field strength and reducing exchange interactions to suppress perpendicular magnetization components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the volume of magnetocrystalline particles is reduced to achieve high-density recording, then recording density is improved, but thermal fluctuations cause signal degradation and magnetization reversal becomes difficult
Solution Approach 1:
The patent applies dynamic microwave fields to the magnetic recording medium during the writing process. The spin torque oscillator generates time-varying magnetic fields that dynamically assist the write head in overcoming thermal fluctuations and achieving reliable magnetization reversal in high-density recording conditions.
Solution Approach 2:
The patent changes the magnetic field parameters by introducing high-frequency microwave fields alongside the DC write field. This parameter change enables effective magnetization reversal at higher recording densities where conventional static fields fail due to thermal stability requirements.
2Device complexity
If a conventional magnetic head is used, then device simplicity is maintained, but recording magnetic field is insufficient for high-density media with high magnetic anisotropy
Solution Approach 1:
The patent creates a composite magnetic head structure combining conventional coil-generated fields with spin torque oscillator-generated microwave fields. This composite approach provides both the DC write field and the high-frequency assist field needed for high-density recording on high-Ku media.
Solution Approach 2:
The spin torque oscillator structure serves multiple functions: it generates the high-frequency magnetic field for microwave-assisted recording, provides spin torque effects for magnetization switching, and integrates with the conventional magnetic head structure. This multi-functionality enables enhanced performance without requiring entirely new head architecture.
3Force
If magnetic field generating layer thickness is increased to enhance high-frequency field strength, then field intensity is improved, but exchange interactions increase causing perpendicular magnetization components
Solution Approach 1:
The patent applies different thicknesses to different magnetic field generating layers within the spin torque oscillator structure. By creating local variations in layer thickness, the patent optimizes the balance between generating sufficient high-frequency field intensity and controlling exchange interactions to maintain proper magnetization orientation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The extended spin torque oscillator achieves a stronger high-frequency magnetic field, enabling effective magnetization reversal and stable recording in high-density magnetic media, improving signal-to-noise ratio and allowing for recording densities exceeding 1 Tbit/in².
Implementation Method 1
the high-frequency magnetic field is generated by alternating the input of magnetic charge on the surface of the magnetic field generating layer (FGL) 110 that reverses magnetization in the surface of the stacked layers due to spin torque actions
Implementation Method 2
a microwave-assisted magnetic recording head with an extended spin torque oscillator is used... enabling effective magnetization reversal and stable recording in high-density magnetic media
Data Source
AI summary
The present disclosure generally relates to a high-frequency oscillator for use in a recording device having a microwave-assisted magnetic recording head. The microwave-assisted magnetic recording head achieves a large assist effect by using an extended spin torque oscillator disposed between a main magnetic pole and a pole opposite the main magnetic pole. The spin torque oscillator obtains a strong high-frequency magnetic field and comprises a first non-magnetic spin scatterer, a reference layer, a first non-magnetic spin transfer layer, a first magnetic field generating layer, a second non-magnetic spin transfer layer, a second magnetic field generating layer, and a second non-magnetic spin scatterer. The spin torque oscillator has a drive current flowing though in the direction from the first magnetic field generating layer to the reference layer.