Dual Spin Torque Oscillator Write Head for MAMR Writability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
As the size of writers in hard disk drives decreases to accommodate increasing digital data storage demands, writability degrades, necessitating improved techniques for writing to magnetic recording media.
Innovation Solution
Implementing a perpendicular magnetic recording writer with dual spin torque oscillators (STOs) that utilize mutual spin transfer torques to drive field-generation layers into large angle oscillations, generating a magnetic field to assist in writing to the magnetic recording medium.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the size of writers is decreased to accommodate increasing digital data storage demands, then areal density capability is improved, but writability degrades
Solution Approach 1:
The patent changes the magnetic field generation mechanism by introducing spin torque oscillators that generate microwave-frequency magnetic fields. This parameter change in the field generation method enables effective writing at smaller sizes by utilizing oscillation effects rather than conventional DC field generation, thereby improving areal density capability while maintaining writability.
Solution Approach 2:
The patent employs spin torque oscillators that generate magnetic fields through oscillating magnetic moments. The oscillation frequency and amplitude are controlled to create effective microwave fields that assist in writing to magnetic media. This vibration-based mechanism enables effective writing at reduced writer sizes, resolving the contradiction between size reduction and writability maintenance.
2Productivity
If a single STO is used, then device complexity is reduced, but write performance is insufficient
Solution Approach 1:
The patent divides the spin torque oscillator into multiple independent STO units (first STO and second STO) with separate FGLs and SILs. Each STO contributes to the overall magnetic field generation, and their combined effect enhances write performance. The segmentation allows for optimized control of each oscillator while achieving superior collective performance.
Solution Approach 2:
The patent merges multiple STOs into a single integrated write head assembly, where the first and second STOs operate simultaneously to generate combined magnetic fields. This merging approach consolidates the complexity into a unified structure while achieving enhanced write performance through the synergistic effect of multiple oscillators.
3Reliability
If FGL oscillates in-phase with itself, then oscillation stability is improved, but detrimental magnetic field components are generated
Solution Approach 1:
The patent introduces asymmetric coupling between the first and second STOs through the shared magnetic path and spin sink structure. This asymmetric configuration causes the FGLs to oscillate in opposite phases, which cancels out detrimental magnetic field components while maintaining stable oscillations. The asymmetry in the magnetic circuit design is key to achieving phase opposition.
Solution Approach 2:
The patent converts the potentially harmful in-phase oscillation mode into a beneficial out-of-phase oscillation mode. By designing the magnetic path to couple the STOs, the system naturally transitions to an out-of-phase oscillation state, which cancels detrimental fields. The coupling mechanism transforms what would be harmful in-phase oscillations into useful out-of-phase oscillations that enhance write performance.
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 dual STO design enhances write performance by maximizing the component of the rf field along the written track direction while minimizing detrimental components, improving writer robustness and areal density capability.
Implementation Method 1
Each STO can include a field-generation layer (FGL) that can oscillate in a same frequency and out of phase with one another. The layers in each STO can enable mutual spin transfer torques between adjacent layers, which can drive the FGLs into a large angle oscillation.
Implementation Method 2
MAMR techniques increase the density of HDDs by using a write head with a spin torque oscillator (STO) to generate a microwave field, which can enhance write performance of the write head to the magnetic recording medium.
Data Source
AI summary
The present embodiments relate to write heads implementing microwave-assisted magnetic recording utilizing multiple spin torque oscillators (STOs). Each STO can include a field-generation layer (FGL) that can oscillate in a same frequency and out of phase with one another. The layers in each STO can enable mutual spin transfer torques between adjacent layers, which can drive the FGLs into a large angle oscillation. The oscillation between the FGLs can cause a magnetic field to be generated that can assist in writing to a magnetic recording medium.